fix(app): add type hint to api_add_photo for Gradio 6.17

Gradio Server API endpoints require type hints on all parameters.
Without str | dict on image_path, server.launch() fails at startup.

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

app.py

@@ -821,7 +821,7 @@ def _build_custom_server():
         return {"garments": catalog, "count": len(catalog)}
 
     @server.api(name="add_photo")
-    def api_add_photo(image_path) -> dict:
+    def api_add_photo(image_path: str | dict) -> dict:
         if isinstance(image_path, dict):
             image_path = image_path.get("path") or image_path.get("url", "")
         results = extract_garments(str(image_path))