profiles: the Personal Secretary retires, and every reference goes with it ...

`secretary` had become a second general-purpose assistant: same models, same
tools, one temperature step apart from `assistant`, and admin-only for no
reason the user could see. The directory is gone and the eight remaining
profiles load clean.

A profile that no longer exists is not a harmless orphan — `Agent` resolves
`session.profile_id` on every run and raises `ProfileNotFound`, so any session
left behind would open and then fail on its first turn. Prod sessions were
moved to `assistant` first (115 rows, verified after), and the local clone
along with them (101).

The reaction fallback loses its role table: it existed because the admin
fallback was itself admin-only, which `assistant` never is. `spawn_agent`
falls back to `assistant` too, and the two prompts that recommended
`secretary` now name only `server_admin` and `developer`.

Add self-recall (scheduled callback) system ...

Core features:
- schedule_recall tool: once/recurring/immediate callbacks
- manage_recall tool: cancel/skip/list scheduled recalls
- Natural-language time parser (ISO, relative, "tomorrow at 09:00")
- PostgreSQL-backed RecallScheduler with lazy pool init
- Background recall_scheduler_loop with asyncio.Semaphore(3)
- _busy_sessions guard prevents user messages during headless runs
- Agent.run() preserves thinking field for session history visibility
- API endpoints: GET/DELETE/POST for session recall, admin list
- Frontend: recall badge, filter, cancel/skip in sidebar and chat header
- Tests: parser, scheduler CRUD, tools, API, scheduler loop (53 tests)
- Manuals: schedule_recall.md and manage_recall.md

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>