feat: switch summarizer to DeepSeek API, add cookie support for transcripts

backend/main.py

@@ -37,6 +37,11 @@ async def startup():
 async def health():
     return {"status": "ok"}
 
+@app.get("/")
+async def root():
+    from fastapi.responses import FileResponse
+    return FileResponse(os.path.join(frontend_build_path, "index.html"))
+
 @app.get("/api/videos")
 async def get_videos(
     status: Optional[str] = "pending",