feat(usage): implement timeout and error handling for antigravity usage and subscription requests

- Add a 10-second timeout for fetch requests in getAntigravityUsage and getAntigravitySubscriptionInfo functions.
- Include error logging for fetch failures in both functions.
- Update headers to include "x-request-source" for MITM bypass.
- Enhance proxyFetch with DNS resolution and MITM bypass capabilities.
- Ensure proxyFetch is loaded in the API route for proper fetch patching.

src/app/api/usage/[connectionId]/route.js

@@ -1,3 +1,6 @@
+// Ensure proxyFetch is loaded to patch globalThis.fetch
+import "open-sse/index.js";
+
 import { getProviderConnectionById, updateProviderConnection } from "@/lib/localDb";
 import { getUsageForProvider } from "open-sse/services/usage.js";
 import { getExecutor } from "open-sse/executors/index.js";