Bugfix/undo fix (#3)

* Add undoLink API function

* Call backend undo on undoLastLink to keep chain in sync

src/api/games.ts

@@ -96,6 +96,10 @@ export async function validateLink(
   return data;
 }
 
+export async function undoLink(gameId: string): Promise<void> {
+  await apiClient.post(`/games/${gameId}/undo`);
+}
+
 export async function getGameSession(id: string): Promise<GameHistoryEntry> {
   const { data } = await apiClient.get<GameHistoryEntry>(`/games/${id}`);
   return data;

src/stores/game-store.ts

@@ -261,6 +261,16 @@ export const useGameStore = create<GameState>((set, get) => ({
       passedMovieB: hasPassedMovieB,
       validationError: null,
     });
+
+    // Fire-and-forget backend undo to keep DB chain in sync
+    const { sessionId } = get();
+    if (sessionId) {
+      import('@/api/games').then(({ undoLink }) => {
+        undoLink(sessionId).catch((err) => {
+          console.error('[GameStore] Failed to undo link on backend:', err);
+        });
+      });
+    }
   },
 
   setValidating: (isValidating: boolean) => set({ isValidating }),