fix: clear thumbnail cache and temp dirs on new session

Co-authored-by: Cursor <cursoragent@cursor.com>

src/lib/bindings/mediaAnalysis.ts

@@ -30,3 +30,7 @@ export async function extractThumbnails(
     duration,
   });
 }
+
+export async function cleanupThumbnails(paths: string[]): Promise<void> {
+  return invoke<void>('cleanup_thumbnails', { paths });
+}