fix: HTML-escape IRC username in Owncast chat, fix WebSocket auth, fix echo suppression

- Escape angle brackets around IRC username so Owncast doesn't swallow
  them as HTML tags (&lt;nick&gt; instead of <nick>)
- Register a chat user via POST /api/chat/register to obtain an
  accessToken, then pass it as a query param when connecting to /ws
  (Owncast closes the WebSocket immediately without one)
- Cache the access token across reconnections; re-register only on
  rejection
- Add ws_display_name config option (default "IRC Bridge")
- Fix echo suppression: record_sent and is_echo now both compare
  raw body instead of mismatched formatted/raw values

Made-with: Cursor

chat-summaries/2026-03-10_21-00-summary.md

@@ -0,0 +1,19 @@
+# Debug: IRC + WebSocket connection failures
+
+## Task
+Investigated why both IRC and WebSocket connections were failing immediately after connecting, entering infinite reconnection loops with exponential backoff.
+
+## Findings
+
+Both issues were **external/environmental**, not code bugs:
+
+1. **IRC** (`irc.zeronode.net`): Server was rejecting with `ERROR :Closing link: ... [No more connections allowed from your host via this connect class (global)]`. Too many existing connections from the same host IP.
+
+2. **WebSocket** (`wss://owncast.bowlafterbowl.com/ws`): Caddy proxy successfully upgraded (101), but the Owncast backend immediately reset the connection. Owncast instance was offline.
+
+## Changes Made
+None (instrumentation added for debugging was fully reverted after diagnosis).
+
+## Follow-up Items
+- Consider logging the actual IRC ERROR message content instead of the generic "IRC stream ended" — would make future diagnosis faster without instrumentation.
+- Consider detecting fatal IRC errors (connection class limits, K-lines) and stopping reconnection attempts rather than continuing to hammer the server.