Fix: handle missing frontend gracefully

app/main.py

@@ -50,8 +50,10 @@ async def health():
 
 # Serve static frontend (will be mounted if exists)
 FRONTEND_DIR = "/app/frontend"
-if os.path.exists(FRONTEND_DIR):
-    app.mount("/assets", StaticFiles(directory=f"{FRONTEND_DIR}/assets"), name="assets")
+ASSETS_DIR = f"{FRONTEND_DIR}/assets"
+
+if os.path.exists(FRONTEND_DIR) and os.path.exists(ASSETS_DIR):
+    app.mount("/assets", StaticFiles(directory=ASSETS_DIR), name="assets")
     
     @app.get("/")
     async def serve_frontend():
@@ -59,17 +61,19 @@ if os.path.exists(FRONTEND_DIR):
     
     @app.get("/{path:path}")
     async def serve_spa(path: str):
+        if path.startswith("api/"):
+            return None  # Let API routes handle
         file_path = f"{FRONTEND_DIR}/{path}"
         if os.path.exists(file_path) and os.path.isfile(file_path):
             return FileResponse(file_path)
         return FileResponse(f"{FRONTEND_DIR}/index.html")
-else:
-    # Fallback: serve basic info page
-    @app.get("/")
-    async def root():
-        return {
-            "service": settings.APP_NAME,
-            "version": settings.APP_VERSION,
-            "docs": "/api/docs",
-            "health": "/api/health"
-        }
+
+# Fallback: serve basic info page when no frontend
+@app.get("/")
+async def root():
+    return {
+        "service": settings.APP_NAME,
+        "version": settings.APP_VERSION,
+        "docs": "/api/docs",
+        "health": "/api/health"
+    }