- Extract markdown-tiptap.ts and yjs-ws-provider.ts to shared/ for reuse
- Thread bodies render as formatted markdown via marked
- Replace compose textarea with TipTap rich-text editor + Yjs collab
- Add formatting toolbar (bold, italic, lists, code, links, etc.)
- Add TipTap comment editor with tiptap-json storage format
- Server accepts content_format on comment API
- Full ProseMirror + collab cursor CSS scoped to shadow DOM
- Editors cleaned up on navigation and disconnect
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
