Add favorites, effects badge on profiles, UI polish

- Add is_favorited column with toggle endpoint and star button on history
- Show sparkles icon on profile cards that have effects configured
- Gold ring on selected profile cards
- Smaller, gray action buttons with brighter hover
- Clamp player time to duration to prevent runaway playback
- Align profile card icon to top for wrapped names
- Flush bottom corners on history card when versions expanded
- Simplify .gitignore data/ rule

app/src/lib/api/client.ts

@@ -218,6 +218,12 @@ class ApiClient {
     });
   }
 
+  async toggleFavorite(generationId: string): Promise<{ is_favorited: boolean }> {
+    return this.request<{ is_favorited: boolean }>(`/history/${generationId}/favorite`, {
+      method: 'POST',
+    });
+  }
+
   // History
   async listHistory(query?: HistoryQuery): Promise<HistoryListResponse> {
     const params = new URLSearchParams();