Thorough animation cleanup when leaving game

- Tag deal container with class so cleanup() can find and remove it
- Remove .traveling-card and .deal-anim-container overlays in cleanup()
- Restore opacity/visibility on cards hidden mid-animation
- Reset all animation flags (dealAnimationInProgress, etc.) in showLobby()

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

client/app.js

@@ -3060,6 +3060,11 @@ class GolfGame {
         if (window.cardAnimations) {
             window.cardAnimations.cancelAll();
         }
+        this.dealAnimationInProgress = false;
+        this.isDrawAnimating = false;
+        this.localDiscardAnimating = false;
+        this.opponentDiscardAnimating = false;
+        this.opponentSwapAnimation = false;
         this.showScreen(this.lobbyScreen);
         this.lobbyError.textContent = '';
         this.roomCode = null;