Title now lives in the page's Yjs 'title' fragment, but two paths corrupted it:
- Rename-revert: a REST/MCP title change wrote only the page.title column,
never the Yjs fragment, so the next editor open replayed the stale Yjs title
and reverted the rename. PageService.update now mirrors the new title into the
Yjs 'title' fragment via CollaborationGateway.writePageTitle, which goes
through openDirectConnection directly (Redis-independent: works with
COLLAB_DISABLE_REDIS and in single-process deployments, unlike the
Redis-routed handleYjsEvent path). The write is best-effort: a Yjs failure is
logged and never rolls back the committed column write. Agent provenance
(actor/aiChatId) is threaded into the store context.
- Untitled-on-open: an empty/just-initialized 'title' fragment clobbered a
non-empty page.title to '' on open. onStoreDocument now treats the title as
changed only when the extracted text is non-empty, covering both the
title-only and body+title save branches. Empty-retitling via collab is
intentionally impossible; the REST DTO is the place to enforce non-empty.
writeTitleFragment does a full clear+seed of the 'title' fragment (no
duplication/concatenation) and leaves the body fragment intact. Removed the dead
useTreeMutation.handleRename path. Adds unit tests for writeTitleFragment, the
gateway write, the anti-empty-clobber guard, and agent provenance.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>