fix: serve static assets from the SPA dist before falling back to index.html

The fallback handler was returning index.html for every non-API path, which meant requests for the bundled logo and any other static file inside frontend/dist landed back as HTML and the browser refused to decode them as images. The handler now checks whether the requested path resolves to a real file under FRONTEND_DIST and serves it directly, keeping the index.html fallback only for client-side router paths.

src/api/main.py

@@ -117,6 +117,9 @@ def _mount_frontend() -> None:
             from fastapi import HTTPException
 
             raise HTTPException(status_code=404, detail="Not found")
+        static_file = FRONTEND_DIST / full_path
+        if full_path and static_file.is_file():
+            return FileResponse(static_file)
         index = FRONTEND_DIST / "index.html"
         if index.exists():
             return FileResponse(index)