fix(ux): 14 cross-platform UX/UI fixes from 500-game audit

Web client (game.js):
- Restart game timer after undo exits auto-complete sequence
- Pause timer while browser tab is hidden (visibilitychange)
- Validate URL seed — NaN / negative falls back to randomSeed()
- Guard onBoardClick/onBoardDblClick during win (snap.is_won)
- Delay win overlay 320 ms so last card CSS transition finishes
- Force reflow in flashIllegal() to restart shake on rapid re-trigger

Android (safe_area.rs):
- Preserve last-known insets on app resume instead of zeroing them;
  eliminates double layout flash on every foreground cycle

All clients — Bevy engine:
- Radial menu: clamp icon anchors to viewport bounds so icons are
  never placed off-screen on narrow phones
- Auto-complete: deactivate state.active when is_auto_completable
  goes false (undo mid-sequence) to stop perpetual background retry
- Touch selection: gate highlight rebuild on is_changed() — was
  despawning/respawning entities every frame unnecessarily
- Input: fire "Tap a pile to move" InfoToast on first tap in
  TapToSelect mode; document cursor_world 1:1 viewport invariant
- Drag threshold: raise desktop from 4 → 6 px to prevent accidental
  drags from cursor jitter on HiDPI displays

Desktop / Android (solitaire_app):
- Call cleanup_orphaned_tmp_files() at startup to remove .tmp files
  left by crashes between atomic write and rename

Design clarification (klondike_adapter.rs):
- Doc comment: Draw-1 recycling is penalty-only by design (never
  blocked) to avoid creating unwinnable positions

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

solitaire_engine/src/auto_complete_plugin.rs

@@ -51,15 +51,15 @@ impl Plugin for AutoCompletePlugin {
         app.init_resource::<AutoCompleteState>()
             .add_message::<RequestRedraw>()
             .add_systems(
-            Update,
-            (
-                detect_auto_complete,
-                on_auto_complete_start,
-                drive_auto_complete,
-            )
-                .chain()
-                .after(GameMutation),
-        );
+                Update,
+                (
+                    detect_auto_complete,
+                    on_auto_complete_start,
+                    drive_auto_complete,
+                )
+                    .chain()
+                    .after(GameMutation),
+            );
     }
 }
 
@@ -83,14 +83,21 @@ fn detect_auto_complete(
     if game.0.is_auto_completable && !state.active {
         state.active = true;
         state.cooldown = AUTO_COMPLETE_INITIAL_DELAY;
+    } else if !game.0.is_auto_completable && state.active {
+        // `is_auto_completable` only becomes false after an explicit undo
+        // (which puts a card back on the tableau or re-fills the stock/waste)
+        // or a new-game reset — never as a transient gap during a normal
+        // auto-complete sequence.  Deactivate here so `drive_auto_complete`
+        // does not keep retrying indefinitely after the player undoes out of
+        // the sequence.
+        //
+        // Note: the transient-`None` case mentioned in older versions of this
+        // comment referred to `next_auto_complete_move()` returning `None`, not
+        // to `is_auto_completable` being false.  Those are independent fields;
+        // `drive_auto_complete` still retries on a transient `None` return from
+        // `next_auto_complete_move` because that check happens there, not here.
+        state.active = false;
     }
-    // Intentionally no `else if !is_auto_completable` branch here.
-    // Deactivating on every frame where `is_auto_completable` is false
-    // would hard-stop the sequence mid-flight whenever `next_auto_complete_move`
-    // transiently returns `None` (e.g. while the previous move is still
-    // in-flight). The `is_won` check above already handles the definitive
-    // end-of-game case; `drive_auto_complete` simply retries next tick
-    // when no move is available yet.
 }
 
 /// Plays a distinct chime the moment auto-complete first activates.
@@ -244,9 +251,7 @@ mod tests {
 
         // Zero out the cooldown so drive fires on the next update regardless
         // of the initial delay constant.
-        app.world_mut()
-            .resource_mut::<AutoCompleteState>()
-            .cooldown = 0.0;
+        app.world_mut().resource_mut::<AutoCompleteState>().cooldown = 0.0;
         app.update(); // drive fires the move
 
         let events = app.world().resource::<Messages<MoveRequestEvent>>();