feat(web): per-machine notices from host status

[futrime]

Unit 2 of the multi-daemon + notifications batch (contracts C3, C4).

What

• C3: Host.status() (and so Daemon.status()) adds pending ([{question, role, text, mode}]), ended ({how, why, epic, at, run, flow, task} or null), epic and task.
• C4: new hmz.web.notices.Notices, held as site.notices, with .since(after), .heard(cb) (returns an unsubscribe callable), .last, .stream(), .look(), .start() and .close().
  • GET /api/notices?after= returns {notices, last}.
  • GET /api/notices/stream sends SSE notice events and resumes from Last-Event-ID or ?last=. With no id given, the stream starts from now.
  • Kinds are done, failed (failed, crashed, budget and refused), stopped, asked (mode ask) and listening (mode listen).
• Polling, never attaching. Places.statuses() reads daemon.daemons() and each .status() when runs are held apart. Otherwise it reads each in-process host's status(). Notices polls it every 2 s. _asks_the_daemon now reuses Places.statuses().
• Startup baseline.
  • The first poll is the baseline.
  • An epic that ended before the first poll is never news, even for a workspace first seen later.
  • A host that does not answer counts as unknown, not as one that has gone.
  • Questions are compared within the same host, by (pid, started), so a new host's q1 is still news.
  • A crash's text is the last line of its traceback.
  • The last 200 notices are kept.
  • Ids come from the clock in milliseconds and always increase, so a client can resume across a restart.
• Docs: docs/reference/daemon.md (status keys) and docs/reference/web.md (Notices API).

Tests

• tests/unit/web/test_notices.py: pure diffing against a fake status source.
• tests/unit/runtime/doing/test_hosting.py: the new status keys.
• tests/integration/test_web_notices.py: through served() and the stand-in agent, a chat produces listening, stopping it produces stopped, and a one-turn flow produces done. It also checks after= and resuming the stream.
• Live check: hmz web --port 0 with runs held apart. The chat produced a listening notice and then stopped, both over curl on the SSE stream and on /api/notices.

🤖 Generated with Claude Code

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.

[futrime]

Landed together in #385.