chore: add pedantic workspace lints (#90)

Add [workspace.lints.rust] and wire each member crate up with
[lints] workspace = true:

  unsafe_code = "deny"        (forbid would break the Android JNI build)
  single_use_lifetimes = "warn"
  trivial_casts = "warn"
  unused_lifetimes = "warn"
  unused_qualifications = "warn"
  variant_size_differences = "warn"
  unexpected_cfgs = "warn"

unsafe_code is "deny" rather than the issue's "forbid" so the three
Android JNI FFI modules (android_keystore, android_clipboard, safe_area)
can opt back in with a scoped #![allow(unsafe_code)] — forbid cannot be
locally overridden. Pure crates carry no unsafe and stay clean.

Clean up the warnings the new lints surface:
- 150ish unused_qualifications removed via `cargo fix` (purely syntactic
  redundant-path-prefix removals).
- table_plugin: the TABLE_COLOUR import was #[cfg(test)]-gated while the
  camera clear-colour used the fully-qualified path; unqualifying it left
  a non-test build with no import. Made the import unconditional instead.
- assets/sources: the `as &[u8]` casts in embed_*_svg! coerce each
  fixed-size &[u8; N] to a uniform slice so the tuples fit the
  &[(&str, &[u8])] arrays — load-bearing, so scoped #[allow(trivial_casts)].

Workspace clippy -D warnings and the full test suite pass. Android build
not compiled here (needs the NDK; built separately per CLAUDE.md §15) —
the deny + scoped-allow keeps the JNI unsafe blocks legal.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

solitaire_engine/src/settings_plugin.rs

@@ -379,8 +379,8 @@ impl Plugin for SettingsPlugin {
             .add_message::<DeleteAccountRequestEvent>()
             .add_message::<ToggleSettingsRequestEvent>()
             .add_message::<InfoToastEvent>()
-            .add_message::<bevy::input::mouse::MouseWheel>()
-            .add_message::<bevy::input::touch::TouchInput>()
+            .add_message::<MouseWheel>()
+            .add_message::<TouchInput>()
             // `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
@@ -2662,7 +2662,7 @@ fn handle_scan_themes(
 
         let themes_dir = user_theme_dir();
 
-        let zips: Vec<std::path::PathBuf> = match std::fs::read_dir(&themes_dir) {
+        let zips: Vec<PathBuf> = match std::fs::read_dir(&themes_dir) {
             Ok(entries) => entries
                 .flatten()
                 .map(|e| e.path())
@@ -3019,7 +3019,7 @@ mod tests {
             unit: MouseScrollUnit::Line,
             x: 0.0,
             y: -3.0,
-            window: bevy::ecs::entity::Entity::PLACEHOLDER,
+            window: Entity::PLACEHOLDER,
         });
         app.update();
         // ScrollPosition must remain at 0.0 — panel was closed.
@@ -3052,7 +3052,7 @@ mod tests {
             unit: MouseScrollUnit::Line,
             x: 0.0,
             y: -2.0,
-            window: bevy::ecs::entity::Entity::PLACEHOLDER,
+            window: Entity::PLACEHOLDER,
         });
         app.update();
         let offset = app
@@ -3364,7 +3364,7 @@ mod tests {
 
     fn fire_resize(app: &mut App, width: f32, height: f32) {
         app.world_mut().write_message(WindowResized {
-            window: bevy::ecs::entity::Entity::PLACEHOLDER,
+            window: Entity::PLACEHOLDER,
             width,
             height,
         });
@@ -3372,7 +3372,7 @@ mod tests {
 
     fn fire_move(app: &mut App, x: i32, y: i32) {
         app.world_mut().write_message(WindowMoved {
-            window: bevy::ecs::entity::Entity::PLACEHOLDER,
+            window: Entity::PLACEHOLDER,
             position: IVec2::new(x, y),
         });
     }
@@ -3494,7 +3494,7 @@ mod tests {
             unit: MouseScrollUnit::Line,
             x: 0.0,
             y: 5.0,
-            window: bevy::ecs::entity::Entity::PLACEHOLDER,
+            window: Entity::PLACEHOLDER,
         });
         app.update();
         let offset = app