Each standalone focus item now auto-creates a linked note and checklist.
Clicking a focus item opens a detail page with side-by-side note editor
(left) and checklist (right) with drag-to-reorder. Save & Return writes
the note and goes back to the focus list. Added focus_id FK to notes and
lists tables, made domain optional when creating from focus context.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>