Adds Figma-style threaded comment markers anchored to data-collab-id
elements across all module pages. Comments stored in per-space Automerge
doc, synced via existing local-first stack. Bell is now context-aware
(canvas pins on canvas, module pins on module pages). Notifications
route through existing WS/push/email system with new module_comment
and module_mention event types.
New files: module-comment-types, module-comment-schemas,
rstack-module-comments component. Updated: shell, comment bell,
notification routes. Added data-collab-id to crowdsurf, rtime, rmeets.
Fixed pre-existing SKILL_LABELS import error in rtime/mod.ts.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
