Fix: no-cache headers for static files, null guards in loadQueue/loadGallery, error boundaries in initializeApp, add paused to queue filter

app/main.py

@@ -19,6 +19,22 @@ import app.upscaler as upscaler
 
 app = FastAPI(title="AI Video Upscaler Dashboard")
 
+# Middleware to prevent browser caching of static files (dev mode)
+from starlette.middleware.base import BaseHTTPMiddleware
+from starlette.requests import Request
+
+class NoCacheStaticMiddleware(BaseHTTPMiddleware):
+    async def dispatch(self, request: Request, call_next):
+        response = await call_next(request)
+        path = request.url.path
+        if path.endswith(('.js', '.css', '.html')) or path == '/':
+            response.headers["Cache-Control"] = "no-cache, no-store, must-revalidate"
+            response.headers["Pragma"] = "no-cache"
+            response.headers["Expires"] = "0"
+        return response
+
+app.add_middleware(NoCacheStaticMiddleware)
+
 # CORS middleware for local development
 app.add_middleware(
     CORSMiddleware,