feat(data,engine): persist replay share URL alongside the replay

The v0.18.0 share-link affordance lived in an in-memory
LastSharedReplayUrl resource that was wiped on quit; the player had
to re-open Stats and re-share within the same session of the win.
The Stats overlay's Prev/Next selector also surfaced older replays
that had no share link at all even when those wins had been
uploaded successfully.

This bundles the URL with the replay it belongs to:

- Replay (solitaire_data) gains share_url: Option<String> with
  #[serde(default)]. No REPLAY_SCHEMA_VERSION bump — older
  replays.json files load unchanged with share_url == None on
  every entry. Replay::new() defaults the field to None.
- poll_replay_upload_result (sync_plugin) writes the resolved URL
  into ReplayHistoryResource::0.replays[0].share_url and persists
  the updated history via save_replay_history_to. The
  cancel-on-replace contract in push_replay_on_win guarantees
  replays[0] is the win whose URL the task is carrying — at most
  one upload is ever in flight, and it's always the most recent
  win.
- handle_copy_share_link_button (stats_plugin) reads from
  history.0.replays[selected.0].share_url instead of
  LastSharedReplayUrl, so the Prev/Next selector's currently-
  displayed replay drives the clipboard contents. Each historical
  win keeps its own URL.
- LastSharedReplayUrl resource removed entirely — its only role
  was bridging the upload-poll system to the Copy button, and
  that channel is now the share_url field on the replay record.

Tests:

- solitaire_data: replay_loads_when_share_url_field_is_absent
  pins backwards-compat — a pre-v0.19.0 Replay JSON without the
  field deserialises with share_url == None.
- solitaire_engine sync_plugin: upload_result_writes_share_url_into_replay_and_persists
  drives a pre-resolved AsyncComputeTaskPool task into
  PendingReplayUpload, pumps update() until the poll system
  resolves it, and asserts both the in-memory replays[0]
  carries the URL and a fresh load_replay_history_from(path)
  picks it up.

Workspace: 1170 passing tests / 0 failing, was 1168 (+2 net).
cargo clippy --workspace --all-targets -- -D warnings clean.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

solitaire_engine/src/stats_plugin.rs

@@ -74,23 +74,13 @@ pub struct StatsCell;
 #[derive(Resource, Debug, Default, Clone)]
 pub struct ReplayHistoryResource(pub ReplayHistory);
 
-/// Most recent shareable replay URL written by `sync_plugin` after the
-/// `SyncProvider::push_replay` task completes successfully. `None`
-/// until the player wins a game on a server-backed sync backend;
-/// repopulated on each subsequent win.
-///
-/// The Stats overlay's "Copy share link" button reads from here and
-/// writes the URL to the OS clipboard via `arboard`. Not persisted to
-/// disk — the URL is recoverable by re-uploading the same replay
-/// (still in `replays.json`), so the session-bound lifetime is fine
-/// for a v1 share affordance.
-#[derive(Resource, Debug, Default, Clone)]
-pub struct LastSharedReplayUrl(pub Option<String>);
-
 /// Marker on the "Copy share link" button inside the Stats modal.
-/// Click writes [`LastSharedReplayUrl`] to the OS clipboard via
-/// `arboard` and surfaces a confirmation toast. Hidden / disabled
-/// when no shareable URL is available.
+/// Click reads the share URL from the currently-selected replay
+/// (`history.0.replays[selected.0].share_url`) and writes it to the
+/// OS clipboard via `arboard`, surfacing a confirmation toast. The
+/// share URL is populated by `sync_plugin::poll_replay_upload_result`
+/// when the corresponding win's upload completes and is persisted to
+/// `replays.json` so it survives a restart.
 #[derive(Component, Debug)]
 pub struct CopyShareLinkButton;
 
@@ -195,7 +185,6 @@ impl Plugin for StatsPlugin {
             .insert_resource(ReplayHistoryResource(initial_history))
             .init_resource::<SelectedReplayIndex>()
             .insert_resource(LatestReplayPath(replay_path))
-            .init_resource::<LastSharedReplayUrl>()
             .add_message::<GameWonEvent>()
             .add_message::<NewGameRequestEvent>()
             .add_message::<ForfeitEvent>()
@@ -299,24 +288,32 @@ fn refresh_replay_history_on_win(
 /// resets the live game to the recorded deal and ticks through the
 /// move list via [`crate::replay_playback`]; the
 /// [`crate::replay_overlay`] banner surfaces while playback runs.
-/// Copies [`LastSharedReplayUrl`] to the OS clipboard via `arboard`
-/// and surfaces a confirmation toast. When no URL is in hand (no win
-/// yet on a server-backed sync backend, local-only mode, or upload
-/// failed) the button still acknowledges the click but explains why
-/// the clipboard wasn't written. `arboard::Clipboard::new()` failures
-/// are logged + surfaced as a generic "couldn't reach the clipboard"
-/// toast rather than swallowed — they're rare but worth diagnosing.
+/// Copies the currently-selected replay's `share_url` to the OS
+/// clipboard via `arboard` and surfaces a confirmation toast. When no
+/// URL is in hand on the selected entry (replay never uploaded — the
+/// player won on a local-only backend, the upload failed, or the
+/// replay pre-dates v0.19.0 share-link persistence) the button still
+/// acknowledges the click but explains why the clipboard wasn't
+/// written. `arboard::Clipboard::new()` failures are logged + surfaced
+/// as a generic "couldn't reach the clipboard" toast rather than
+/// swallowed — they're rare but worth diagnosing.
 fn handle_copy_share_link_button(
     buttons: Query<&Interaction, (With<CopyShareLinkButton>, Changed<Interaction>)>,
-    last_url: Res<LastSharedReplayUrl>,
+    history: Res<ReplayHistoryResource>,
+    selected: Res<SelectedReplayIndex>,
     mut toast: MessageWriter<InfoToastEvent>,
 ) {
     if !buttons.iter().any(|i| *i == Interaction::Pressed) {
         return;
     }
-    let Some(url) = last_url.0.as_ref() else {
+    let Some(url) = history
+        .0
+        .replays
+        .get(selected.0)
+        .and_then(|r| r.share_url.as_ref())
+    else {
         toast.write(InfoToastEvent(
-            "No share link yet \u{2014} win a game on a server-backed sync to upload one.".to_string(),
+            "No share link for this replay \u{2014} win a game on a server-backed sync to upload one.".to_string(),
         ));
         return;
     };