Fix asset 404 by explicitly mounting /assets

toothmap_backend/main.py

@@ -243,4 +243,5 @@ async def segment_unet(file: UploadFile = File(...)):
 
 # --- Mount React Frontend ---
 # This MUST be the last route registered so it doesn't shadow API routes
+app.mount("/assets", StaticFiles(directory="static/assets"), name="assets")
 app.mount("/", StaticFiles(directory="static", html=True), name="static")