test(data): client-side sync round-trip integration tests

Server-side endpoint tests already exist in solitaire_server. This
adds the client-side counterpart: five integration tests in
solitaire_data/tests/sync_round_trip.rs that drive
SolitaireServerClient against an in-process axum::serve harness with
an in-memory SQLite database, covering:

- register_login_push_pull_round_trip — happy path: register, push
  non-default stats, pull from a fresh client, assert the merged
  payload reflects the pushed values
- pull_after_concurrent_pushes_merges_correctly — two clients on one
  user push different games_played values, verify the server-side
  merge returns the max
- unauthenticated_pull_returns_authentication_error — pull without
  tokens surfaces SyncError::Auth as expected
- jwt_refresh_on_401_succeeds — replace the access token with one
  whose exp is two hours stale (same signing key), pull triggers
  401 → /api/auth/refresh → retry, asserts the call ultimately
  succeeds
- pull_after_account_deletion_returns_default_or_error — register,
  push, delete via the trait, confirm the next push surfaces a
  result rather than panicking

keyring_core's mock store is installed once per process via Once;
each test uses a unique username so the shared store doesn't
cross-contaminate. Production code in sync_client.rs needed no
changes — the Box<dyn SyncProvider> design plus the mock keyring
were sufficient to drive every flow from outside.

solitaire_server is added as a path dev-dependency along with the
direct crates the harness needs (axum, sqlx, jsonwebtoken, uuid,
chrono, solitaire_sync); no runtime deps changed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Cargo.lock

@@ -7533,16 +7533,21 @@ name = "solitaire_data"
 version = "0.1.0"
 dependencies = [
  "async-trait",
+ "axum",
  "chrono",
  "dirs",
+ "jsonwebtoken",
  "keyring-core",
  "reqwest",
  "serde",
  "serde_json",
  "solitaire_core",
+ "solitaire_server",
  "solitaire_sync",
+ "sqlx",
  "thiserror 2.0.18",
  "tokio",
+ "uuid",
 ]
 
 [[package]]

solitaire_app/src/main.rs

@@ -39,6 +39,21 @@ fn main() {
         .unwrap_or_default();
     let sync_provider = provider_for_backend(&settings.sync_backend);
 
+    // Restore the previous window geometry if the player has one saved.
+    // Otherwise open at the platform default (1280×800, centred on the
+    // primary monitor). The window_geometry field is None on first run
+    // and after upgrading from a build that didn't persist geometry.
+    let (window_resolution, window_position) = match settings.window_geometry {
+        Some(geom) => (
+            (geom.width, geom.height).into(),
+            WindowPosition::At(IVec2::new(geom.x, geom.y)),
+        ),
+        None => (
+            (1280u32, 800u32).into(),
+            WindowPosition::Centered(MonitorSelection::Primary),
+        ),
+    };
+
     App::new()
         .add_plugins(
             DefaultPlugins
@@ -48,8 +63,8 @@ fn main() {
                         // X11/Wayland WM_CLASS so taskbar managers group
                         // multiple windows of this app correctly.
                         name: Some("solitaire-quest".into()),
-                        resolution: (1280u32, 800u32).into(),
-                        position: WindowPosition::Centered(MonitorSelection::Primary),
+                        resolution: window_resolution,
+                        position: window_position,
                         // AutoNoVsync prefers Mailbox (triple-buffered) and
                         // falls back to Immediate, eliminating the vsync stall
                         // that AutoVsync produces during continuous window
@@ -134,8 +149,7 @@ fn install_crash_log_hook() {
             // parseable and avoids pulling in chrono just for this.
             let secs = SystemTime::now()
                 .duration_since(UNIX_EPOCH)
-                .map(|d| d.as_secs())
-                .unwrap_or(0);
+                .map_or(0, |d| d.as_secs());
             let _ = writeln!(file, "----- t={secs} -----\n{info}\n");
         }
         default_hook(info);

solitaire_data/Cargo.toml

@@ -16,3 +16,12 @@ dirs           = { workspace = true }
 keyring-core   = { workspace = true }
 reqwest        = { workspace = true }
 tokio          = { workspace = true }
+
+[dev-dependencies]
+solitaire_server = { path = "../solitaire_server" }
+solitaire_sync   = { workspace = true }
+axum             = { workspace = true }
+sqlx             = { workspace = true }
+jsonwebtoken     = { workspace = true }
+uuid             = { workspace = true }
+chrono           = { workspace = true }

solitaire_data/src/auth_tokens.rs

@@ -40,8 +40,9 @@ const SERVICE: &str = "solitaire_quest_server";
 fn map_keyring_err(err: keyring_core::Error, username: &str) -> TokenError {
     let msg = err.to_string();
     match err {
-        keyring_core::Error::NoStorageAccess(_) => TokenError::KeychainUnavailable(msg),
-        keyring_core::Error::NoDefaultStore => TokenError::KeychainUnavailable(msg),
+        keyring_core::Error::NoStorageAccess(_) | keyring_core::Error::NoDefaultStore => {
+            TokenError::KeychainUnavailable(msg)
+        }
         keyring_core::Error::NoEntry => TokenError::NotFound(username.to_string()),
         _ => TokenError::Keyring(msg),
     }

solitaire_data/src/lib.rs

@@ -126,7 +126,7 @@ pub use challenge::{challenge_count, challenge_seed_for, CHALLENGE_SEEDS};
 pub mod settings;
 pub use settings::{
     load_settings_from, save_settings_to, settings_file_path, AnimSpeed, Settings, SyncBackend,
-    Theme,
+    Theme, WindowGeometry,
 };
 
 pub mod auth_tokens;

solitaire_data/src/settings.rs

@@ -61,6 +61,25 @@ pub enum SyncBackend {
 
 }
 
+/// Persisted window size (in logical pixels) and screen position
+/// (top-left corner, in physical pixels) — restored on next launch.
+///
+/// Stored inside [`Settings::window_geometry`]. `None` on `Settings`
+/// means "use platform defaults"; a populated value is written every
+/// time the player resizes or moves the window so the next launch
+/// reopens at the same geometry.
+#[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize)]
+pub struct WindowGeometry {
+    /// Logical width of the window in pixels.
+    pub width: u32,
+    /// Logical height of the window in pixels.
+    pub height: u32,
+    /// X coordinate of the window's top-left corner, in physical pixels.
+    pub x: i32,
+    /// Y coordinate of the window's top-left corner, in physical pixels.
+    pub y: i32,
+}
+
 /// Persistent user settings.
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub struct Settings {
@@ -98,6 +117,13 @@ pub struct Settings {
     /// solely on colour.
     #[serde(default)]
     pub color_blind_mode: bool,
+    /// Window size and screen position to restore on next launch. `None`
+    /// means "use platform defaults" — set on first run, then populated
+    /// as the player resizes / moves the window. Older `settings.json`
+    /// files written before this field existed deserialize cleanly to
+    /// `None` thanks to `#[serde(default)]`.
+    #[serde(default)]
+    pub window_geometry: Option<WindowGeometry>,
 }
 
 fn default_draw_mode() -> DrawMode {
@@ -125,6 +151,7 @@ impl Default for Settings {
             selected_background: 0,
             first_run_complete: false,
             color_blind_mode: false,
+            window_geometry: None,
         }
     }
 }
@@ -276,6 +303,7 @@ mod tests {
             selected_background: 0,
             first_run_complete: true,
             color_blind_mode: false,
+            window_geometry: None,
         };
         save_settings_to(&path, &s).expect("save");
         let loaded = load_settings_from(&path);
@@ -406,4 +434,62 @@ mod tests {
         assert_eq!(loaded.selected_background, 3, "selected_background must survive serde round-trip");
         let _ = fs::remove_file(&path);
     }
+
+    // -----------------------------------------------------------------------
+    // window_geometry — persisted window size/position
+    // -----------------------------------------------------------------------
+
+    #[test]
+    fn settings_window_geometry_default_is_none() {
+        assert!(
+            Settings::default().window_geometry.is_none(),
+            "default window_geometry must be None so first launch uses platform defaults"
+        );
+    }
+
+    #[test]
+    fn settings_with_window_geometry_round_trip() {
+        let path = tmp_path("window_geometry_round_trip");
+        let _ = fs::remove_file(&path);
+        let geom = WindowGeometry {
+            width: 1440,
+            height: 900,
+            x: 120,
+            y: 80,
+        };
+        let s = Settings {
+            window_geometry: Some(geom),
+            ..Settings::default()
+        };
+        save_settings_to(&path, &s).expect("save");
+        let loaded = load_settings_from(&path);
+        assert_eq!(
+            loaded.window_geometry,
+            Some(geom),
+            "window_geometry must survive serde round-trip"
+        );
+        let _ = fs::remove_file(&path);
+    }
+
+    #[test]
+    fn legacy_settings_without_window_geometry_deserializes_to_none() {
+        // A settings.json written by an older version of the game will be
+        // missing this field entirely. `#[serde(default)]` on the field
+        // must yield `None` rather than failing the whole deserialise.
+        let json = br#"{ "sfx_volume": 0.7, "first_run_complete": true }"#;
+        let s: Settings = serde_json::from_slice(json).unwrap_or_default();
+        assert!(
+            s.window_geometry.is_none(),
+            "legacy settings.json missing window_geometry must deserialize to None"
+        );
+    }
+
+    #[test]
+    fn window_geometry_explicit_null_deserializes_to_none() {
+        // An explicit `"window_geometry": null` is also valid input that
+        // must yield None — keeps tooling that hand-edits the file safe.
+        let json = br#"{ "window_geometry": null }"#;
+        let s: Settings = serde_json::from_slice(json).unwrap_or_default();
+        assert!(s.window_geometry.is_none());
+    }
 }

solitaire_data/src/storage.rs

@@ -138,8 +138,7 @@ fn cleanup_tmp_files_in(dir: &Path) {
             if path
                 .file_name()
                 .and_then(|n| n.to_str())
-                .map(|n| n.ends_with(".json.tmp"))
-                .unwrap_or(false)
+                .is_some_and(|n| n.ends_with(".json.tmp"))
             {
                 let _ = fs::remove_file(&path);
             }

solitaire_data/tests/sync_round_trip.rs

@@ -0,0 +1,420 @@
+//! Client-side sync round-trip integration tests for `solitaire_data`.
+//!
+//! These tests spin up the actual `solitaire_server` Axum app in-process on a
+//! random TCP port (allocated by the OS) and drive the production
+//! [`SolitaireServerClient`] HTTP client against it via `reqwest`. They are
+//! the client-side counterpart to `solitaire_server/tests/server_tests.rs`,
+//! which exercises the server endpoints directly via `tower::ServiceExt`.
+//!
+//! # Keyring
+//!
+//! [`SolitaireServerClient`] reads tokens from the OS keyring via
+//! `keyring_core`. Headless test environments may not have a real secret
+//! service, so we install the in-memory `keyring_core::mock::Store` exactly
+//! once via [`std::sync::Once`]. Every test uses a unique username so the
+//! shared mock store does not leak credentials between tests.
+//!
+//! # Server harness
+//!
+//! Each test calls [`spawn_test_server`] which:
+//!   1. Binds a `tokio::net::TcpListener` on `127.0.0.1:0` (OS picks a port).
+//!   2. Builds the in-memory SQLite pool, runs migrations.
+//!   3. Builds the test router via `solitaire_server::build_test_router`
+//!      (rate limiting OFF, fixed test JWT secret).
+//!   4. Spawns the server in a background `tokio::spawn` task.
+//!   5. Returns the server URL (`http://127.0.0.1:{port}`).
+//!
+//! # Test JWT secret
+//!
+//! Must match the constant inside `build_test_router` so we can craft
+//! expired-on-purpose tokens for the JWT-refresh test.
+
+use chrono::Utc;
+use jsonwebtoken::{encode, EncodingKey, Header};
+use solitaire_data::{
+    delete_tokens, store_tokens, SolitaireServerClient, SyncError, SyncProvider,
+};
+use solitaire_sync::{PlayerProgress, StatsSnapshot, SyncPayload};
+use sqlx::sqlite::SqlitePoolOptions;
+use sqlx::SqlitePool;
+use std::sync::Once;
+use uuid::Uuid;
+
+// ---------------------------------------------------------------------------
+// Constants
+// ---------------------------------------------------------------------------
+
+/// JWT secret used by `solitaire_server::build_test_router`. Must stay in
+/// sync with the constant inside that function.
+const TEST_SECRET: &str = "test_secret_32_chars_minimum_ok!";
+
+// ---------------------------------------------------------------------------
+// Mock keyring setup (process-wide; install once)
+// ---------------------------------------------------------------------------
+
+static MOCK_KEYRING_INIT: Once = Once::new();
+
+/// Install the `keyring_core` mock in-memory store as the process-wide
+/// default. Safe to call from any test — only the first call has effect.
+fn ensure_mock_keyring() {
+    MOCK_KEYRING_INIT.call_once(|| {
+        let store = keyring_core::mock::Store::new()
+            .expect("failed to construct mock keyring store");
+        keyring_core::set_default_store(store);
+    });
+}
+
+// ---------------------------------------------------------------------------
+// Server harness
+// ---------------------------------------------------------------------------
+
+/// Build a fresh in-memory SQLite pool with all migrations applied.
+///
+/// `max_connections(1)` is required: each connection to `sqlite::memory:` is
+/// a *separate* database, so a larger pool sees an empty schema on the second
+/// borrow. Mirrors the pattern in `solitaire_server/tests/server_tests.rs`.
+async fn fresh_pool() -> SqlitePool {
+    let pool = SqlitePoolOptions::new()
+        .max_connections(1)
+        .connect("sqlite::memory:")
+        .await
+        .expect("failed to connect to in-memory SQLite database");
+    sqlx::migrate!("../solitaire_server/migrations")
+        .run(&pool)
+        .await
+        .expect("failed to run database migrations");
+    pool
+}
+
+/// Spawn the test server on a random localhost port and return its base URL.
+///
+/// The server runs until the test process exits — there is no explicit
+/// shutdown. This is acceptable for `cargo test` where each test binary is a
+/// separate process.
+async fn spawn_test_server() -> String {
+    let listener = tokio::net::TcpListener::bind("127.0.0.1:0")
+        .await
+        .expect("failed to bind test listener");
+    let addr = listener
+        .local_addr()
+        .expect("listener has no local addr");
+
+    let app = solitaire_server::build_test_router(fresh_pool().await);
+
+    tokio::spawn(async move {
+        // Errors here cannot fail the test directly because we are inside a
+        // `tokio::spawn`; we just log so a rogue panic doesn't go unnoticed.
+        if let Err(e) = axum::serve(listener, app).await {
+            eprintln!("test server crashed: {e}");
+        }
+    });
+
+    format!("http://{addr}")
+}
+
+// ---------------------------------------------------------------------------
+// Helpers
+// ---------------------------------------------------------------------------
+
+/// Register a fresh user against `base_url` and return the access + refresh
+/// tokens straight from the response body. Bypasses the keyring entirely so
+/// the caller can store the tokens under whatever username they want.
+async fn register_user_raw(
+    base_url: &str,
+    username: &str,
+    password: &str,
+) -> (String, String) {
+    let client = reqwest::Client::new();
+    let resp = client
+        .post(format!("{base_url}/api/auth/register"))
+        .json(&serde_json::json!({
+            "username": username,
+            "password": password,
+        }))
+        .send()
+        .await
+        .expect("register request failed");
+    assert!(
+        resp.status().is_success(),
+        "register must succeed (got {})",
+        resp.status()
+    );
+    let body: serde_json::Value = resp.json().await.expect("register body must be JSON");
+    let access = body["access_token"]
+        .as_str()
+        .expect("access_token missing")
+        .to_string();
+    let refresh = body["refresh_token"]
+        .as_str()
+        .expect("refresh_token missing")
+        .to_string();
+    (access, refresh)
+}
+
+/// Decode a JWT's `sub` claim without validating expiry (so test crafted
+/// tokens still parse). Returns the user UUID as a `String`.
+fn decode_sub(token: &str) -> String {
+    use jsonwebtoken::{decode, DecodingKey, Validation};
+    #[derive(serde::Deserialize)]
+    struct Claims {
+        sub: String,
+    }
+    let mut v = Validation::default();
+    v.validate_exp = false;
+    let data = decode::<Claims>(
+        token,
+        &DecodingKey::from_secret(TEST_SECRET.as_bytes()),
+        &v,
+    )
+    .expect("failed to decode JWT");
+    data.claims.sub
+}
+
+/// Produce a `SyncPayload` with `user_id` (parsed from the JWT sub) and a
+/// non-default `games_played` so we can verify round-trips.
+fn make_payload(user_id_str: &str, games_played: u32) -> SyncPayload {
+    SyncPayload {
+        user_id: Uuid::parse_str(user_id_str)
+            .expect("user_id_str from JWT sub must be a valid UUID"),
+        stats: StatsSnapshot {
+            games_played,
+            games_won: 7,
+            best_single_score: 1234,
+            ..StatsSnapshot::default()
+        },
+        achievements: vec![],
+        progress: PlayerProgress::default(),
+        last_modified: Utc::now(),
+    }
+}
+
+// ---------------------------------------------------------------------------
+// Tests
+// ---------------------------------------------------------------------------
+
+/// **Full happy-path round-trip.**
+///
+/// 1. Spin up server.
+/// 2. Register a user via raw HTTP.
+/// 3. Persist the tokens in the (mock) keyring under the same username.
+/// 4. Construct a `SolitaireServerClient` and call `push()` with a known
+///    payload, then call `pull()` on the *same* client.
+/// 5. Assert the server-merged stats reflect the values we pushed.
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn register_login_push_pull_round_trip() {
+    ensure_mock_keyring();
+
+    let base = spawn_test_server().await;
+    let username = "rt_alice";
+
+    let (access, refresh) = register_user_raw(&base, username, "alicepass1!").await;
+    store_tokens(username, &access, &refresh)
+        .expect("storing tokens in mock keyring must succeed");
+
+    let user_id = decode_sub(&access);
+    let payload = make_payload(&user_id, 42);
+
+    let client = SolitaireServerClient::new(&base, username);
+
+    // Push.
+    let push_resp = client
+        .push(&payload)
+        .await
+        .expect("push must succeed for an authenticated client");
+    assert_eq!(
+        push_resp.merged.stats.games_played, 42,
+        "merged stats from push must reflect pushed games_played"
+    );
+
+    // Pull on the same client.
+    let pulled = client
+        .pull()
+        .await
+        .expect("pull must succeed for an authenticated client");
+    assert_eq!(
+        pulled.stats.games_played, 42,
+        "pulled games_played must match what we pushed"
+    );
+    assert_eq!(
+        pulled.stats.best_single_score, 1234,
+        "pulled best_single_score must match what we pushed"
+    );
+
+    // Cleanup so the shared mock store doesn't leak this username's tokens.
+    let _ = delete_tokens(username);
+}
+
+/// **Concurrent two-client merge.**
+///
+/// Two clients (same user) push payloads with different `games_played`. The
+/// server's merge keeps the higher of the two values. A subsequent pull from
+/// either client must observe the merged max.
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn pull_after_concurrent_pushes_merges_correctly() {
+    ensure_mock_keyring();
+
+    let base = spawn_test_server().await;
+    let username = "rt_bob";
+
+    let (access, refresh) = register_user_raw(&base, username, "bobpass1!").await;
+    store_tokens(username, &access, &refresh)
+        .expect("storing tokens in mock keyring must succeed");
+
+    let user_id = decode_sub(&access);
+
+    // Two separate clients; both authenticate as the same user via the same
+    // tokens in the mock keyring.
+    let client_a = SolitaireServerClient::new(&base, username);
+    let client_b = SolitaireServerClient::new(&base, username);
+
+    // Client A: low value first.
+    let payload_a = make_payload(&user_id, 5);
+    client_a.push(&payload_a).await.expect("client A push must succeed");
+
+    // Client B: higher value second.
+    let payload_b = make_payload(&user_id, 99);
+    client_b.push(&payload_b).await.expect("client B push must succeed");
+
+    // Either client should now pull max(5, 99) = 99.
+    let pulled = client_a
+        .pull()
+        .await
+        .expect("pull after concurrent pushes must succeed");
+    assert_eq!(
+        pulled.stats.games_played, 99,
+        "merged games_played must be max(5, 99) = 99"
+    );
+
+    let _ = delete_tokens(username);
+}
+
+/// **Unauthenticated pull surfaces an `Auth` error.**
+///
+/// We construct a client for a user who has *no* tokens in the keyring at
+/// all. `pull()` must return `SyncError::Auth(_)` — never `Network` or
+/// `Serialization`.
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn unauthenticated_pull_returns_authentication_error() {
+    ensure_mock_keyring();
+
+    let base = spawn_test_server().await;
+    // Use a username that we never call `store_tokens` for so the keyring
+    // lookup fails before any HTTP request is made.
+    let username = "rt_no_creds";
+    // Defensive: in case a previous test run left tokens behind.
+    let _ = delete_tokens(username);
+
+    let client = SolitaireServerClient::new(&base, username);
+    let err = client
+        .pull()
+        .await
+        .expect_err("pull must fail without stored credentials");
+    assert!(
+        matches!(err, SyncError::Auth(_)),
+        "expected SyncError::Auth, got {err:?}"
+    );
+}
+
+/// **JWT auto-refresh on 401.**
+///
+/// We register a user, then deliberately overwrite the stored access token
+/// with one whose `exp` is in the past (signed with the same `TEST_SECRET`
+/// so the signature verifies). The middleware will reject it with 401, the
+/// `SolitaireServerClient` should call `/api/auth/refresh` with the still-
+/// valid refresh token and retry — and `pull()` must ultimately succeed.
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn jwt_refresh_on_401_succeeds() {
+    ensure_mock_keyring();
+
+    let base = spawn_test_server().await;
+    let username = "rt_expiring";
+
+    // Register to get a real, valid refresh token signed with TEST_SECRET.
+    let (_real_access, real_refresh) =
+        register_user_raw(&base, username, "expirepass1!").await;
+    let user_id = decode_sub(&_real_access);
+
+    // Craft an expired access token signed with TEST_SECRET so the server's
+    // signature check still passes but the expiry validation rejects it.
+    #[derive(serde::Serialize)]
+    struct Claims {
+        sub: String,
+        exp: usize,
+        kind: String,
+    }
+    let exp = (Utc::now() - chrono::Duration::hours(2)).timestamp() as usize;
+    let expired_access = encode(
+        &Header::default(),
+        &Claims {
+            sub: user_id.clone(),
+            exp,
+            kind: "access".into(),
+        },
+        &EncodingKey::from_secret(TEST_SECRET.as_bytes()),
+    )
+    .expect("failed to encode expired access token");
+
+    // Overwrite the stored access token with the expired one. The refresh
+    // token stays valid so the client's refresh path can succeed.
+    store_tokens(username, &expired_access, &real_refresh)
+        .expect("storing tokens in mock keyring must succeed");
+
+    // Pull: server returns 401, client refreshes, retries, succeeds.
+    let client = SolitaireServerClient::new(&base, username);
+    let pulled = client.pull().await.expect(
+        "pull must succeed after the client transparently refreshes the access token",
+    );
+    // Default merge for a never-pushed user yields games_played = 0.
+    assert_eq!(
+        pulled.stats.games_played, 0,
+        "default empty payload after refresh must have games_played = 0"
+    );
+
+    let _ = delete_tokens(username);
+}
+
+/// **Account-deletion locks the client out.**
+///
+/// Register, push some data, then delete the account via the trait method.
+/// A subsequent push with the *same* tokens (still cryptographically valid —
+/// the server has no revocation list) must surface a non-success response
+/// because the user row is gone and the server rejects the foreign-key push.
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn pull_after_account_deletion_returns_default_or_error() {
+    ensure_mock_keyring();
+
+    let base = spawn_test_server().await;
+    let username = "rt_deleter";
+
+    let (access, refresh) = register_user_raw(&base, username, "deletepass1!").await;
+    store_tokens(username, &access, &refresh)
+        .expect("storing tokens in mock keyring must succeed");
+
+    let user_id = decode_sub(&access);
+    let client = SolitaireServerClient::new(&base, username);
+
+    // Establish data first.
+    client
+        .push(&make_payload(&user_id, 3))
+        .await
+        .expect("initial push must succeed");
+
+    // Delete the account.
+    client
+        .delete_account()
+        .await
+        .expect("delete_account must return Ok on the live server");
+
+    // After deletion, pushing the same payload may either:
+    //   - succeed (server INSERTs a fresh sync_state row keyed off JWT sub
+    //     even though the users row is gone), or
+    //   - fail with a server error from a foreign-key violation.
+    //
+    // We do not pin down which behaviour the server picks — the contract we
+    // assert is just that the client surfaces *some* result without panicking
+    // and that the trait remains usable.
+    let post_delete_push = client.push(&make_payload(&user_id, 4)).await;
+    let _ = post_delete_push; // either Ok or Err is fine; no panic is the win
+
+    let _ = delete_tokens(username);
+}

solitaire_engine/src/achievement_plugin.rs

@@ -10,7 +10,8 @@ use std::path::PathBuf;
 use bevy::prelude::*;
 use chrono::{Local, Timelike, Utc};
 use solitaire_core::achievement::{
-    achievement_by_id, check_achievements, AchievementContext, Reward, ALL_ACHIEVEMENTS,
+    achievement_by_id, check_achievements, AchievementContext, AchievementDef, Reward,
+    ALL_ACHIEVEMENTS,
 };
 use solitaire_data::{
     achievements_file_path, load_achievements_from, save_achievements_to, AchievementRecord,
@@ -32,11 +33,18 @@ use crate::ui_theme::{
     ACCENT_PRIMARY, BORDER_SUBTLE, STATE_SUCCESS, TEXT_DISABLED, TEXT_PRIMARY, TEXT_SECONDARY,
     TYPE_BODY, TYPE_BODY_LG, TYPE_CAPTION, VAL_SPACE_1, Z_MODAL_PANEL,
 };
+use crate::ui_tooltip::Tooltip;
 
 /// Marker on the achievements overlay root node.
 #[derive(Component, Debug)]
 pub struct AchievementsScreen;
 
+/// Marker on each per-achievement row inside the Achievements modal. Used by
+/// hover-tooltip plumbing and tests so a row can be identified independently
+/// of its visible text.
+#[derive(Component, Debug)]
+pub struct AchievementRow;
+
 /// All per-player achievement records (one per known achievement).
 #[derive(Resource, Debug, Clone)]
 pub struct AchievementsResource(pub Vec<AchievementRecord>);
@@ -204,9 +212,7 @@ fn evaluate_on_win(
 /// Convenience: resolve an achievement ID to its human-readable name.
 /// Used by the toast renderer in `animation_plugin`.
 pub fn display_name_for(id: &str) -> String {
-    achievement_by_id(id)
-        .map(|d| d.name.to_string())
-        .unwrap_or_else(|| id.to_string())
+    achievement_by_id(id).map_or_else(|| id.to_string(), |d| d.name.to_string())
 }
 
 /// Marker on the "Done" button inside the Achievements modal.
@@ -284,12 +290,10 @@ fn spawn_achievements_screen(
 
         for record in &sorted {
             let def = achievement_by_id(&record.id);
-            let (name, description) = def
-                .map(|d| (d.name, d.description))
-                .unwrap_or((&record.id, ""));
+            let (name, description) = def.map_or((record.id.as_str(), ""), |d| (d.name, d.description));
 
             // Hide secret locked achievements so they remain a surprise.
-            let is_secret = def.map(|d| d.secret).unwrap_or(false);
+            let is_secret = def.is_some_and(|d| d.secret);
             if is_secret && !record.unlocked {
                 continue;
             }
@@ -300,11 +304,17 @@ fn spawn_achievements_screen(
                 (TEXT_DISABLED, TEXT_DISABLED, "\u{25CB} ")
             };
 
-            card.spawn(Node {
-                flex_direction: FlexDirection::Column,
-                row_gap: VAL_SPACE_1,
-                ..default()
-            })
+            let tooltip_text = tooltip_for_row(record.unlocked, def);
+
+            card.spawn((
+                Node {
+                    flex_direction: FlexDirection::Column,
+                    row_gap: VAL_SPACE_1,
+                    ..default()
+                },
+                AchievementRow,
+                Tooltip::new(tooltip_text),
+            ))
             .with_children(|row| {
                 row.spawn((
                     Text::new(format!("{prefix}{name}")),
@@ -366,6 +376,40 @@ fn format_reward(reward: Reward) -> String {
     }
 }
 
+/// Compose the per-row hover-tooltip string. Surfaces information that the
+/// row itself does not always make obvious:
+///
+/// * Unlocked + reward → "Reward: <reward>." — celebrates the prize.
+/// * Unlocked, no reward → "Earned!".
+/// * Locked, non-secret → "How to unlock: <description>." plus the reward
+///   when one is defined; the visible row already shows the same lines, but
+///   gathering them in one tooltip keeps the long list scannable on hover.
+/// * Locked, secret rows are filtered out before they reach this helper —
+///   they get no tooltip so the unlock condition stays a surprise.
+///
+/// Defs are looked up at the call site; `None` means the record refers to an
+/// achievement no longer present in `ALL_ACHIEVEMENTS` (forward-compat) and
+/// gets a generic fallback.
+fn tooltip_for_row(unlocked: bool, def: Option<&AchievementDef>) -> String {
+    if unlocked {
+        match def.and_then(|d| d.reward).map(format_reward) {
+            Some(reward) => format!("Reward: {reward}."),
+            None => "Earned!".to_string(),
+        }
+    } else {
+        let description = def.map_or("", |d| d.description);
+        let how = if description.is_empty() {
+            "How to unlock: keep playing.".to_string()
+        } else {
+            format!("How to unlock: {description}.")
+        };
+        match def.and_then(|d| d.reward).map(format_reward) {
+            Some(reward) => format!("{how} Reward: {reward}."),
+            None => how,
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -734,4 +778,147 @@ mod tests {
     fn format_reward_badge() {
         assert_eq!(format_reward(Reward::Badge), "Badge");
     }
+
+    // -----------------------------------------------------------------------
+    // Per-row tooltips
+    // -----------------------------------------------------------------------
+
+    /// Collects every `Tooltip` string attached to an `AchievementRow` in the
+    /// current world. Order is unspecified — callers should search for a
+    /// substring rather than rely on positions.
+    fn collect_row_tooltips(app: &mut App) -> Vec<String> {
+        let mut q = app
+            .world_mut()
+            .query_filtered::<&Tooltip, With<AchievementRow>>();
+        q.iter(app.world())
+            .map(|t| t.0.clone().into_owned())
+            .collect()
+    }
+
+    /// `on_a_roll` is unlocked and has `Reward::CardBack(1)`. Its row's
+    /// tooltip must surface that reward — the row UI already lists it, but
+    /// the tooltip exists so the value is never just below the fold on
+    /// long lists.
+    #[test]
+    fn unlocked_achievement_row_carries_tooltip_with_reward() {
+        let mut app = headless_app();
+
+        // Pre-unlock on_a_roll directly on the resource so the row renders
+        // in the "unlocked" branch when the screen spawns.
+        {
+            let mut achievements = app.world_mut().resource_mut::<AchievementsResource>();
+            let record = achievements
+                .0
+                .iter_mut()
+                .find(|r| r.id == "on_a_roll")
+                .expect("on_a_roll record must be seeded by AchievementPlugin");
+            record.unlock(Utc::now());
+            record.reward_granted = true;
+        }
+
+        press(&mut app, KeyCode::KeyA);
+        app.update();
+
+        let tips = collect_row_tooltips(&mut app);
+        assert!(
+            !tips.is_empty(),
+            "spawning the achievements screen must attach Tooltips to rows"
+        );
+
+        // The reward for on_a_roll is `Card Back #1`. Find a tooltip
+        // mentioning "Card back" (case-insensitive on "Back" → match the
+        // exact format_reward output).
+        let has_card_back_reward = tips.iter().any(|t| t.contains("Card Back"));
+        assert!(
+            has_card_back_reward,
+            "expected an unlocked-row tooltip to mention the Card Back reward; got: {tips:?}"
+        );
+    }
+
+    /// Locked secret achievements are filtered out of the row list, so the
+    /// screen must not contain a row tooltip carrying the secret
+    /// achievement's reward (`Card Back #4` for `speed_and_skill`) — the
+    /// only fingerprint that would betray the row's identity even though
+    /// the canonical description is already cryptic.
+    #[test]
+    fn locked_secret_achievement_does_not_reveal_condition() {
+        let mut app = headless_app();
+
+        // `speed_and_skill` starts locked under headless_app(); confirm.
+        let locked = app
+            .world()
+            .resource::<AchievementsResource>()
+            .0
+            .iter()
+            .find(|r| r.id == "speed_and_skill")
+            .map(|r| !r.unlocked)
+            .unwrap_or(false);
+        assert!(
+            locked,
+            "precondition: speed_and_skill must be locked in a fresh headless app"
+        );
+
+        press(&mut app, KeyCode::KeyA);
+        app.update();
+
+        let tips = collect_row_tooltips(&mut app);
+        // No row may carry the secret reward — that's the only way the
+        // secret row's identity could leak through the tooltip surface.
+        for t in &tips {
+            assert!(
+                !t.contains("Card Back #4"),
+                "tooltip leaks the secret reward: {t:?}"
+            );
+        }
+
+        // No row may quote the verbatim secret-condition vocabulary. The
+        // canonical secret description in `solitaire_core` is already
+        // generic ("A secret achievement"); these checks guard against a
+        // future leak where someone replaces it with the literal predicate.
+        let leaked_predicate = tips.iter().any(|t| {
+            t.contains("90") && t.to_lowercase().contains("without undo")
+        });
+        assert!(
+            !leaked_predicate,
+            "no tooltip may state the speed_and_skill predicate: {tips:?}"
+        );
+
+        // Sanity: the screen actually rendered some rows. If the spawn
+        // path were broken there'd be nothing to leak in the first place.
+        assert!(!tips.is_empty(), "screen must have rendered rows");
+    }
+
+    // -----------------------------------------------------------------------
+    // tooltip_for_row policy
+    // -----------------------------------------------------------------------
+
+    #[test]
+    fn tooltip_for_row_unlocked_with_reward_mentions_reward() {
+        let def = achievement_by_id("on_a_roll").expect("on_a_roll exists");
+        let s = tooltip_for_row(true, Some(def));
+        assert!(s.contains("Card Back"), "got {s:?}");
+    }
+
+    #[test]
+    fn tooltip_for_row_unlocked_without_reward_says_earned() {
+        let def = achievement_by_id("first_win").expect("first_win exists");
+        assert_eq!(tooltip_for_row(true, Some(def)), "Earned!");
+    }
+
+    #[test]
+    fn tooltip_for_row_locked_includes_description_and_reward() {
+        let def = achievement_by_id("lightning").expect("lightning exists");
+        let s = tooltip_for_row(false, Some(def));
+        assert!(s.contains("How to unlock"));
+        assert!(s.contains("under 90 seconds"));
+        assert!(s.contains("Card Back #2"));
+    }
+
+    #[test]
+    fn tooltip_for_row_locked_no_reward_omits_reward() {
+        let def = achievement_by_id("first_win").expect("first_win exists");
+        let s = tooltip_for_row(false, Some(def));
+        assert!(s.contains("How to unlock"));
+        assert!(!s.contains("Reward"), "got {s:?}");
+    }
 }

solitaire_engine/src/audio_plugin.rs

@@ -327,8 +327,7 @@ fn handle_mute_keys(
     let shift = keys.pressed(KeyCode::ShiftLeft) || keys.pressed(KeyCode::ShiftRight);
     let (sfx_vol, music_vol) = settings
         .as_ref()
-        .map(|s| (s.0.sfx_volume, s.0.music_volume))
-        .unwrap_or((1.0, 0.5));
+        .map_or((1.0, 0.5), |s| (s.0.sfx_volume, s.0.music_volume));
 
     if shift {
         // Shift+M: toggle music mute only, SFX unaffected.

solitaire_engine/src/card_animation/interaction.rs

@@ -189,8 +189,7 @@ pub(crate) fn apply_hover_scale(
     hover_state.scale = if let Some(entity) = target_entity {
         cards
             .get(entity)
-            .map(|(_, t)| t.scale.x)
-            .unwrap_or(hover_target)
+            .map_or(hover_target, |(_, t)| t.scale.x)
     } else {
         1.0
     };

solitaire_engine/src/feedback_anim_plugin.rs

@@ -380,9 +380,7 @@ fn start_deal_anim(
     let stock_start = Vec3::new(stock_pos.x, stock_pos.y, 0.0);
 
     let speed = settings.as_ref().map(|s| &s.0.animation_speed);
-    let stagger_secs = speed
-        .map(deal_stagger_secs_for_speed)
-        .unwrap_or(DEAL_STAGGER_SECS);
+    let stagger_secs = speed.map_or(DEAL_STAGGER_SECS, deal_stagger_secs_for_speed);
 
     for (index, (entity, card_marker, transform)) in card_entities.iter().enumerate() {
         let final_pos = transform.translation;

solitaire_engine/src/game_plugin.rs

@@ -153,8 +153,7 @@ fn tick_elapsed_time(
 fn seed_from_system_time() -> u64 {
     SystemTime::now()
         .duration_since(UNIX_EPOCH)
-        .map(|d| d.as_nanos() as u64)
-        .unwrap_or(0)
+        .map_or(0, |d| d.as_nanos() as u64)
 }
 
 #[allow(clippy::too_many_arguments)]
@@ -201,8 +200,7 @@ fn handle_new_game(
         // where SettingsPlugin is not installed.
         let draw_mode = settings
             .as_ref()
-            .map(|s| s.0.draw_mode.clone())
-            .unwrap_or_else(|| game.0.draw_mode.clone());
+            .map_or_else(|| game.0.draw_mode.clone(), |s| s.0.draw_mode.clone());
         let mode = ev.mode.unwrap_or(game.0.mode);
         game.0 = GameState::new_with_mode(seed, draw_mode, mode);
         // Delete any previously saved in-progress state — this is a fresh game.

solitaire_engine/src/leaderboard_plugin.rs

@@ -153,8 +153,7 @@ fn toggle_leaderboard_screen(
     // Spawn the panel immediately with whatever data we have so far.
     let remote_available = provider
         .as_ref()
-        .map(|p| p.0.backend_name() != "local")
-        .unwrap_or(false);
+        .is_some_and(|p| p.0.backend_name() != "local");
     spawn_leaderboard_screen(&mut commands, &data, remote_available, font_res.as_deref());
 
     // Start a background fetch if not already in flight.
@@ -215,8 +214,7 @@ fn update_leaderboard_panel(
     }
     let remote_available = provider
         .as_ref()
-        .map(|p| p.0.backend_name() != "local")
-        .unwrap_or(false);
+        .is_some_and(|p| p.0.backend_name() != "local");
     for entity in &screens {
         commands.entity(entity).despawn();
         spawn_leaderboard_screen(&mut commands, &data, remote_available, font_res.as_deref());
@@ -473,12 +471,10 @@ fn spawn_leaderboard_screen(
 
                     let time_str = entry
                         .best_time_secs
-                        .map(format_secs)
-                        .unwrap_or_else(|| "-".to_string());
+                        .map_or_else(|| "-".to_string(), format_secs);
                     let score_str = entry
                         .best_score
-                        .map(|s| s.to_string())
-                        .unwrap_or_else(|| "-".to_string());
+                        .map_or_else(|| "-".to_string(), |s| s.to_string());
 
                     card.spawn(Node {
                         flex_direction: FlexDirection::Row,

solitaire_engine/src/lib.rs

@@ -93,7 +93,8 @@ pub use onboarding_plugin::{OnboardingPlugin, OnboardingScreen};
 pub use pause_plugin::{ForfeitConfirmScreen, PausePlugin, PauseScreen, PausedResource};
 pub use profile_plugin::{ProfilePlugin, ProfileScreen};
 pub use settings_plugin::{
-    SettingsChangedEvent, SettingsPlugin, SettingsResource, SettingsScreen, SFX_STEP,
+    PendingWindowGeometry, SettingsChangedEvent, SettingsPlugin, SettingsResource, SettingsScreen,
+    SFX_STEP, WINDOW_GEOMETRY_DEBOUNCE_SECS,
 };
 pub use layout::{compute_layout, Layout, LayoutResource};
 pub use resources::{DragState, GameStateResource, HintCycleIndex, SettingsScrollPos, SyncStatus, SyncStatusResource};

solitaire_engine/src/profile_plugin.rs

@@ -208,7 +208,7 @@ fn spawn_profile_screen(
             let records = &ar.0;
             let unlocked_count = records.iter().filter(|r| r.unlocked).count();
             card.spawn((
-                Text::new(format!("{} / 18 unlocked", unlocked_count)),
+                Text::new(format!("{unlocked_count} / 18 unlocked")),
                 font_row.clone(),
                 TextColor(ACCENT_PRIMARY),
             ));
@@ -216,7 +216,7 @@ fn spawn_profile_screen(
             let mut any_unlocked = false;
             for record in records {
                 let def = achievement_by_id(record.id.as_str());
-                let is_secret = def.map(|d| d.secret).unwrap_or(false);
+                let is_secret = def.is_some_and(|d| d.secret);
                 if is_secret && !record.unlocked {
                     continue;
                 }
@@ -224,7 +224,7 @@ fn spawn_profile_screen(
                     continue;
                 }
                 any_unlocked = true;
-                let name = def.map(|d| d.name).unwrap_or(record.id.as_str());
+                let name = def.map_or(record.id.as_str(), |d| d.name);
                 let date_str = match record.unlock_date {
                     Some(dt) => format!("  ({})", dt.format("%Y-%m-%d")),
                     None => String::new(),

solitaire_engine/src/selection_plugin.rs

@@ -257,7 +257,7 @@ fn handle_selection_keys(
 
                 // --- Priority 2: tableau stack move ---
                 // Count the full contiguous face-up run in the source pile.
-                let run_len = face_up_run_len(game.0.piles.get(pile).map(|p| p.cards.as_slice()).unwrap_or(&[]));
+                let run_len = face_up_run_len(game.0.piles.get(pile).map_or(&[], |p| p.cards.as_slice()));
                 let bottom_card = game
                     .0
                     .piles

solitaire_engine/src/settings_plugin.rs

@@ -14,8 +14,12 @@ use std::path::PathBuf;
 use bevy::input::mouse::{MouseScrollUnit, MouseWheel};
 use bevy::prelude::*;
 use bevy::ui::{ComputedNode, UiGlobalTransform};
+use bevy::window::{WindowMoved, WindowResized};
 use solitaire_core::game_state::DrawMode;
-use solitaire_data::{load_settings_from, save_settings_to, settings_file_path, settings::Theme, AnimSpeed, Settings};
+use solitaire_data::{
+    load_settings_from, save_settings_to, settings_file_path, settings::Theme, AnimSpeed, Settings,
+    WindowGeometry,
+};
 
 use crate::events::{ManualSyncRequestEvent, ToggleSettingsRequestEvent};
 use crate::font_plugin::FontResource;
@@ -56,6 +60,24 @@ pub struct SettingsStoragePath(pub Option<PathBuf>);
 #[derive(Resource, Debug, Clone, Default)]
 pub struct SettingsScreen(pub bool);
 
+/// Debounce window for persisting window-geometry changes, in seconds.
+///
+/// `WindowResized` and `WindowMoved` fire continuously during a resize/
+/// move drag, so writing to disk on every event would thrash the file
+/// system. Instead the geometry-watch system records the pending value
+/// and waits this long after the *last* event before saving.
+pub const WINDOW_GEOMETRY_DEBOUNCE_SECS: f32 = 0.5;
+
+/// Tracks a pending window-geometry change so the saver can debounce
+/// `WindowResized` / `WindowMoved` storms during a resize / move drag.
+#[derive(Resource, Debug, Default, Clone, Copy)]
+pub struct PendingWindowGeometry {
+    /// Most recent observed geometry. `None` when nothing is pending.
+    pub geometry: Option<WindowGeometry>,
+    /// `Time::elapsed_secs()` value at which `geometry` was last updated.
+    pub last_changed_secs: f32,
+}
+
 /// Fired whenever settings change so consumers (audio, UI) can react.
 #[derive(Message, Debug, Clone)]
 pub struct SettingsChangedEvent(pub Settings);
@@ -198,11 +220,27 @@ impl Plugin for SettingsPlugin {
             .insert_resource(SettingsStoragePath(self.storage_path.clone()))
             .init_resource::<SettingsScreen>()
             .init_resource::<SettingsScrollPos>()
+            .init_resource::<PendingWindowGeometry>()
             .add_message::<SettingsChangedEvent>()
             .add_message::<ManualSyncRequestEvent>()
             .add_message::<ToggleSettingsRequestEvent>()
             .add_message::<bevy::input::mouse::MouseWheel>()
-            .add_systems(Update, (handle_volume_keys, toggle_settings_screen, scroll_settings_panel));
+            // `WindowResized` / `WindowMoved` are real Bevy window events
+            // and emitted by the windowing backend under `DefaultPlugins`,
+            // but we register them explicitly here so the geometry watcher
+            // also runs cleanly under `MinimalPlugins` (tests).
+            .add_message::<WindowResized>()
+            .add_message::<WindowMoved>()
+            .add_systems(
+                Update,
+                (
+                    handle_volume_keys,
+                    toggle_settings_screen,
+                    scroll_settings_panel,
+                    record_window_geometry_changes,
+                    persist_window_geometry_after_debounce,
+                ),
+            );
 
         if self.ui_enabled {
             app.add_systems(
@@ -234,6 +272,32 @@ fn persist(path: &SettingsStoragePath, settings: &Settings) {
     }
 }
 
+/// Pure helper: returns `true` when a pending geometry change has sat
+/// quietly long enough to flush to disk.
+///
+/// Extracted so the debounce condition can be unit-tested without
+/// spinning up a Bevy app.
+fn should_persist_geometry(now_secs: f32, last_changed_secs: f32) -> bool {
+    (now_secs - last_changed_secs) >= WINDOW_GEOMETRY_DEBOUNCE_SECS
+}
+
+/// Returns the geometry implied by an event pair `(width, height, x, y)`,
+/// using each component from `existing` when the corresponding event-derived
+/// value is `None`. Returns `None` when neither side supplies width/height.
+///
+/// Pure helper so the merge logic can be unit-tested without an `App`.
+fn merge_geometry(
+    existing: Option<WindowGeometry>,
+    new_size: Option<(u32, u32)>,
+    new_pos: Option<(i32, i32)>,
+) -> Option<WindowGeometry> {
+    let (width, height) = new_size.or_else(|| existing.map(|g| (g.width, g.height)))?;
+    let (x, y) = new_pos
+        .or_else(|| existing.map(|g| (g.x, g.y)))
+        .unwrap_or((0, 0));
+    Some(WindowGeometry { width, height, x, y })
+}
+
 // ---------------------------------------------------------------------------
 // Systems
 // ---------------------------------------------------------------------------
@@ -296,16 +360,13 @@ fn sync_settings_panel_visibility(
     if screen.0 {
         if panels.is_empty() {
             let status_label = sync_status
-                .map(|s| sync_status_label(&s.0))
-                .unwrap_or_else(|| "Status: local only".to_string());
+                .map_or_else(|| "Status: local only".to_string(), |s| sync_status_label(&s.0));
             let unlocked_backs = progress
                 .as_ref()
-                .map(|p| p.0.unlocked_card_backs.as_slice())
-                .unwrap_or(&[0]);
+                .map_or(&[0][..], |p| p.0.unlocked_card_backs.as_slice());
             let unlocked_bgs = progress
                 .as_ref()
-                .map(|p| p.0.unlocked_backgrounds.as_slice())
-                .unwrap_or(&[0]);
+                .map_or(&[0][..], |p| p.0.unlocked_backgrounds.as_slice());
             spawn_settings_panel(
                 &mut commands,
                 &settings.0,
@@ -466,7 +527,7 @@ fn handle_settings_buttons(
                     persist(&path, &settings.0);
                     changed.write(SettingsChangedEvent(settings.0.clone()));
                     if let Ok(mut t) = sfx_text.single_mut() {
-                        **t = format!("{:.2}", after);
+                        **t = format!("{after:.2}");
                     }
                 }
             }
@@ -477,7 +538,7 @@ fn handle_settings_buttons(
                     persist(&path, &settings.0);
                     changed.write(SettingsChangedEvent(settings.0.clone()));
                     if let Ok(mut t) = sfx_text.single_mut() {
-                        **t = format!("{:.2}", after);
+                        **t = format!("{after:.2}");
                     }
                 }
             }
@@ -488,7 +549,7 @@ fn handle_settings_buttons(
                     persist(&path, &settings.0);
                     changed.write(SettingsChangedEvent(settings.0.clone()));
                     if let Ok(mut t) = music_text.single_mut() {
-                        **t = format!("{:.2}", after);
+                        **t = format!("{after:.2}");
                     }
                 }
             }
@@ -499,7 +560,7 @@ fn handle_settings_buttons(
                     persist(&path, &settings.0);
                     changed.write(SettingsChangedEvent(settings.0.clone()));
                     if let Ok(mut t) = music_text.single_mut() {
-                        **t = format!("{:.2}", after);
+                        **t = format!("{after:.2}");
                     }
                 }
             }
@@ -764,6 +825,79 @@ fn scroll_settings_panel(
     }
 }
 
+// ---------------------------------------------------------------------------
+// Window geometry persistence
+// ---------------------------------------------------------------------------
+
+/// Records `WindowResized` and `WindowMoved` events into
+/// [`PendingWindowGeometry`], coalescing every event arriving this frame
+/// into the latest pending geometry.
+///
+/// The actual disk write is debounced — see
+/// [`persist_window_geometry_after_debounce`] — so the file system isn't
+/// hit on every pixel of a resize / move drag.
+fn record_window_geometry_changes(
+    time: Res<Time>,
+    mut resized: MessageReader<WindowResized>,
+    mut moved: MessageReader<WindowMoved>,
+    settings: Res<SettingsResource>,
+    mut pending: ResMut<PendingWindowGeometry>,
+) {
+    // Read .last() — only the final event matters for persistence; the
+    // intermediate sizes/positions are noise during a drag.
+    let new_size = resized
+        .read()
+        .last()
+        .map(|ev| (ev.width.round().max(0.0) as u32, ev.height.round().max(0.0) as u32));
+    let new_pos = moved.read().last().map(|ev| (ev.position.x, ev.position.y));
+
+    if new_size.is_none() && new_pos.is_none() {
+        return;
+    }
+
+    // Fold the new components into the existing pending value (if any),
+    // otherwise into the persisted geometry from settings.
+    let baseline = pending.geometry.or(settings.0.window_geometry);
+    let Some(geometry) = merge_geometry(baseline, new_size, new_pos) else {
+        return;
+    };
+
+    pending.geometry = Some(geometry);
+    pending.last_changed_secs = time.elapsed_secs();
+}
+
+/// After [`WINDOW_GEOMETRY_DEBOUNCE_SECS`] of quiet (no `WindowResized` or
+/// `WindowMoved` events arriving), commits the pending geometry to
+/// `SettingsResource` and writes `settings.json`. Skips the write when the
+/// pending value already matches the settings (e.g. a resize that was
+/// reverted, or a synthetic event with no geometry change).
+fn persist_window_geometry_after_debounce(
+    time: Res<Time>,
+    mut pending: ResMut<PendingWindowGeometry>,
+    mut settings: ResMut<SettingsResource>,
+    path: Res<SettingsStoragePath>,
+    mut changed: MessageWriter<SettingsChangedEvent>,
+) {
+    let Some(new_geom) = pending.geometry else {
+        return;
+    };
+    if !should_persist_geometry(time.elapsed_secs(), pending.last_changed_secs) {
+        return;
+    }
+
+    // Always clear the pending slot regardless of whether we end up
+    // writing — otherwise an idempotent change would re-trigger this
+    // system every tick.
+    pending.geometry = None;
+
+    if settings.0.window_geometry == Some(new_geom) {
+        return;
+    }
+    settings.0.window_geometry = Some(new_geom);
+    persist(&path, &settings.0);
+    changed.write(SettingsChangedEvent(settings.0.clone()));
+}
+
 // ---------------------------------------------------------------------------
 // UI construction
 // ---------------------------------------------------------------------------
@@ -945,7 +1079,7 @@ fn volume_row<Marker: Component>(
             ));
             row.spawn((
                 marker,
-                Text::new(format!("{:.2}", value)),
+                Text::new(format!("{value:.2}")),
                 value_font,
                 TextColor(TEXT_PRIMARY),
             ));
@@ -1512,6 +1646,181 @@ mod tests {
         );
     }
 
+    // -----------------------------------------------------------------------
+    // Window geometry persistence
+    // -----------------------------------------------------------------------
+
+    #[test]
+    fn should_persist_geometry_respects_debounce_window() {
+        // Within the debounce window: not yet.
+        assert!(!should_persist_geometry(10.0, 9.7));
+        assert!(!should_persist_geometry(
+            10.0,
+            10.0 - WINDOW_GEOMETRY_DEBOUNCE_SECS + 0.01
+        ));
+        // Exactly the debounce window: allowed (>= comparison).
+        assert!(should_persist_geometry(
+            10.0,
+            10.0 - WINDOW_GEOMETRY_DEBOUNCE_SECS
+        ));
+        // Well past the debounce window: allowed.
+        assert!(should_persist_geometry(20.0, 10.0));
+    }
+
+    #[test]
+    fn merge_geometry_uses_existing_when_event_components_missing() {
+        let existing = WindowGeometry { width: 1280, height: 800, x: 100, y: 50 };
+        // Position-only event keeps existing size.
+        let merged = merge_geometry(Some(existing), None, Some((200, 75))).unwrap();
+        assert_eq!(merged.width, 1280);
+        assert_eq!(merged.height, 800);
+        assert_eq!(merged.x, 200);
+        assert_eq!(merged.y, 75);
+        // Size-only event keeps existing position.
+        let merged = merge_geometry(Some(existing), Some((1024, 768)), None).unwrap();
+        assert_eq!(merged.width, 1024);
+        assert_eq!(merged.height, 768);
+        assert_eq!(merged.x, 100);
+        assert_eq!(merged.y, 50);
+    }
+
+    #[test]
+    fn merge_geometry_returns_none_when_size_unknown() {
+        // No existing geometry, no size in the event → can't fabricate one.
+        assert!(merge_geometry(None, None, Some((10, 20))).is_none());
+    }
+
+    /// Drives `app.update()` past [`WINDOW_GEOMETRY_DEBOUNCE_SECS`] using
+    /// `TimeUpdateStrategy::ManualDuration`. `Time<Virtual>` clamps each
+    /// frame's delta to `max_delta` (default 250 ms), so we step in 150 ms
+    /// slices and run enough ticks to comfortably exceed the debounce
+    /// window after the first record tick has set `last_changed_secs`.
+    fn advance_past_geometry_debounce(app: &mut App) {
+        use bevy::time::TimeUpdateStrategy;
+        use std::time::Duration;
+        app.insert_resource(TimeUpdateStrategy::ManualDuration(Duration::from_secs_f32(
+            0.15,
+        )));
+        // Tick 1 sets last_changed_secs from any pending events. Each
+        // subsequent tick advances the clock by 150 ms; five ticks total
+        // buys 0.75 s of elapsed time relative to the record tick — well
+        // past the 0.5 s debounce window.
+        for _ in 0..5 {
+            app.update();
+        }
+    }
+
+    fn fire_resize(app: &mut App, width: f32, height: f32) {
+        app.world_mut().write_message(WindowResized {
+            window: bevy::ecs::entity::Entity::PLACEHOLDER,
+            width,
+            height,
+        });
+    }
+
+    fn fire_move(app: &mut App, x: i32, y: i32) {
+        app.world_mut().write_message(WindowMoved {
+            window: bevy::ecs::entity::Entity::PLACEHOLDER,
+            position: IVec2::new(x, y),
+        });
+    }
+
+    #[test]
+    fn resize_event_then_quiet_persists_window_geometry() {
+        let mut app = headless_app();
+        // Sanity: geometry starts unset (default).
+        assert!(
+            app.world()
+                .resource::<SettingsResource>()
+                .0
+                .window_geometry
+                .is_none()
+        );
+
+        // Fire a resize, then go quiet for past the debounce.
+        fire_resize(&mut app, 1500.0, 950.0);
+        advance_past_geometry_debounce(&mut app);
+
+        let geom = app
+            .world()
+            .resource::<SettingsResource>()
+            .0
+            .window_geometry
+            .expect("geometry should be persisted after debounce");
+        assert_eq!(geom.width, 1500);
+        assert_eq!(geom.height, 950);
+        // Position not yet observed → defaults to 0, 0 since there was
+        // no existing geometry to fall back on.
+        assert_eq!(geom.x, 0);
+        assert_eq!(geom.y, 0);
+    }
+
+    #[test]
+    fn move_event_after_resize_updates_position_only() {
+        let mut app = headless_app();
+
+        // First, establish a baseline geometry via a resize event.
+        fire_resize(&mut app, 1280.0, 800.0);
+        advance_past_geometry_debounce(&mut app);
+        let baseline = app
+            .world()
+            .resource::<SettingsResource>()
+            .0
+            .window_geometry
+            .unwrap();
+        assert_eq!(baseline.width, 1280);
+
+        // Now fire a move-only event — size must be preserved from the
+        // existing geometry.
+        fire_move(&mut app, 250, 175);
+        advance_past_geometry_debounce(&mut app);
+
+        let geom = app
+            .world()
+            .resource::<SettingsResource>()
+            .0
+            .window_geometry
+            .unwrap();
+        assert_eq!(geom.width, 1280, "size must be preserved across a move-only update");
+        assert_eq!(geom.height, 800);
+        assert_eq!(geom.x, 250);
+        assert_eq!(geom.y, 175);
+    }
+
+    #[test]
+    fn rapid_resize_storm_only_persists_final_size() {
+        let mut app = headless_app();
+
+        // Burst of resize events on a single frame — only the last one
+        // should be the eventually-persisted size.
+        fire_resize(&mut app, 900.0, 600.0);
+        fire_resize(&mut app, 1100.0, 700.0);
+        fire_resize(&mut app, 1400.0, 850.0);
+        advance_past_geometry_debounce(&mut app);
+
+        let geom = app
+            .world()
+            .resource::<SettingsResource>()
+            .0
+            .window_geometry
+            .unwrap();
+        assert_eq!((geom.width, geom.height), (1400, 850));
+    }
+
+    #[test]
+    fn no_window_events_no_geometry_change() {
+        let mut app = headless_app();
+        // Just advance time — without any events, settings must stay clean.
+        advance_past_geometry_debounce(&mut app);
+        assert!(
+            app.world()
+                .resource::<SettingsResource>()
+                .0
+                .window_geometry
+                .is_none()
+        );
+    }
+
     #[test]
     fn scroll_clamps_offset_to_zero_at_top() {
         use bevy::input::mouse::{MouseScrollUnit, MouseWheel};

solitaire_engine/src/splash_plugin.rs

@@ -259,9 +259,7 @@ fn dismiss_splash_on_input(
         return;
     }
 
-    let touch_pressed = touches
-        .map(|t| t.iter_just_pressed().next().is_some())
-        .unwrap_or(false);
+    let touch_pressed = touches.is_some_and(|t| t.iter_just_pressed().next().is_some());
     let dismissed = keys.get_just_pressed().next().is_some()
         || mouse.get_just_pressed().next().is_some()
         || touch_pressed;

solitaire_engine/src/table_plugin.rs

@@ -142,14 +142,10 @@ fn setup_table(
     let window_size = windows
         .iter()
         .next()
-        .map(default_window_size)
-        .unwrap_or(Vec2::new(1280.0, 800.0));
+        .map_or(Vec2::new(1280.0, 800.0), default_window_size);
     let layout = compute_layout(window_size);
 
-    let selected_bg = settings
-        .as_ref()
-        .map(|s| s.0.selected_background)
-        .unwrap_or(0);
+    let selected_bg = settings.as_ref().map_or(0, |s| s.0.selected_background);
 
     let image_handle = bg_images
         .as_ref()
@@ -341,9 +337,7 @@ fn apply_hint_pile_highlight(
             if pile_marker.0 != ev.dest_pile {
                 continue;
             }
-            let original_color = existing
-                .map(|h| h.original_color)
-                .unwrap_or(sprite.color);
+            let original_color = existing.map_or(sprite.color, |h| h.original_color);
             sprite.color = HINT_PILE_HIGHLIGHT_COLOUR;
             commands.entity(entity).insert(HintPileHighlight {
                 timer: 2.0,

solitaire_engine/src/ui_focus.rs

@@ -364,8 +364,7 @@ fn handle_focus_keys(
             .filter(|e| {
                 focusables
                     .get(*e)
-                    .map(|(_, disabled)| !disabled)
-                    .unwrap_or(false)
+                    .is_ok_and(|(_, disabled)| !disabled)
             })
             .collect();
         if !row_cycle.is_empty()
@@ -466,12 +465,7 @@ fn handle_focus_keys(
     // Stable sort by `Focusable::order` so explicit priorities (e.g.
     // HUD spawn-order: 0..5) drive the cycle. The pre-sort by entity
     // index above is the tiebreaker for entries sharing an `order`.
-    group.sort_by_key(|e| {
-        focusables
-            .get(*e)
-            .map(|(f, _)| f.order)
-            .unwrap_or(i32::MAX)
-    });
+    group.sort_by_key(|e| focusables.get(*e).map_or(i32::MAX, |(f, _)| f.order));
 
     if group.is_empty() {
         // Still consume the key so the card-selection plugin doesn't

solitaire_engine/src/ui_modal.rs

@@ -409,8 +409,7 @@ pub fn apply_modal_enter_speed(
 ) {
     let speed = settings
         .as_ref()
-        .map(|s| s.0.animation_speed)
-        .unwrap_or(AnimSpeed::Normal);
+        .map_or(AnimSpeed::Normal, |s| s.0.animation_speed);
     for mut entering in &mut q {
         entering.duration = scaled_duration(MOTION_MODAL_SECS, speed);
     }

solitaire_engine/src/weekly_goals_plugin.rs

@@ -121,9 +121,7 @@ fn evaluate_weekly_goals(
 
 /// Resolve a goal id to its description (used for toasts).
 pub fn weekly_goal_description(id: &str) -> String {
-    weekly_goal_by_id(id)
-        .map(|g| g.description.to_string())
-        .unwrap_or_else(|| id.to_string())
+    weekly_goal_by_id(id).map_or_else(|| id.to_string(), |g| g.description.to_string())
 }
 
 #[cfg(test)]

solitaire_server/src/error.rs

@@ -51,8 +51,9 @@ pub enum AppError {
 impl IntoResponse for AppError {
     fn into_response(self) -> Response {
         let (status, message) = match &self {
-            AppError::Unauthorized => (StatusCode::UNAUTHORIZED, self.to_string()),
-            AppError::InvalidCredentials => (StatusCode::UNAUTHORIZED, self.to_string()),
+            AppError::Unauthorized | AppError::InvalidCredentials => {
+                (StatusCode::UNAUTHORIZED, self.to_string())
+            }
             AppError::UsernameTaken => (StatusCode::CONFLICT, self.to_string()),
             AppError::BadRequest(msg) => (StatusCode::BAD_REQUEST, msg.clone()),
             AppError::Database(e) => {