fix(ai): frontend console error — remove broken tracker (agent)

- Remove `wss://open.video.lukewarlow.uk:443/announce` from `DEFAULT_WSS_TRACKERS` in `js/constants.js`.
- This tracker was returning `net::ERR_SSL_PROTOCOL_ERROR`, causing console noise and connection failures.
- Added `scripts/agent/debug_frontend.py` to help diagnose frontend initialization errors.

Verified with `scripts/agent/debug_frontend.py` that the error is resolved.
Ran `npm run format`, `npm run lint`, and `npm run test:unit`.

js/constants.js

@@ -110,7 +110,6 @@ const DEFAULT_WSS_TRACKERS = Object.freeze([
   "wss://tracker.btorrent.xyz",
   "wss://tracker.novage.com.ua:443/announce",
   "wss://tracker.webtorrent.dev",
-  "wss://open.video.lukewarlow.uk:443/announce",
 ]);
 
 const SANITIZED_DEFAULT_BLUR_THRESHOLD = coerceNonNegativeInteger(