feat(m7): markdown notes with CRUD, preview, search, tests, e2e
- ProjectNoteRepository (CRUD, soft-delete, search title/body/tags,
pinned-first ordering, index usage) + NoteService (membership permission,
author/admin edit/delete, note_updated notification to other members,
note_created/note_updated activity logs, pin/tags)
- APIs: notes list/create/detail/edit/delete
- Screens: notes list + NoteForm, note detail + NoteEditor + MarkdownBody
preview, ProjectNav メモ link
- Unit tests (ProjectNoteRepository, NoteService) + e2e markdown-notes.spec
e45aea8e27