**Palace Code self-heal complete.** Here's the summary:

**All features working:**
- Page loads correctly with header, split-panel layout, thread list, time window selector, new chat button
- All API endpoints responding: `/code/api/threads` (10 threads), `/code/api/session-tails` (5 entries), `/code/api/linear-issues` (74 issues), and all write endpoints

**One bug fixed:**
- `apps/palacebutler/src/chat.ts` — filter for browser elements wasn't guarding against objects with `null` `tag` properties, causing recurring `Cannot read properties of null (reading 'tag')` errors in the server log. Fixed by adding `&& e.tag != null` to the filter.

**Observations (not bugs, no action needed):**
- `showLog` state in ThreadDetail has no trigger — dead code path, but inline log display works fine
- Several components (`ChatReply`, `NewChatBar`, etc.) are unused legacy code