v0.4.1

Lifecycle patch over v0.4.0. Three resume/shutdown bugs that surfaced
during the v0.4 SQLite live test.

Lane A — Pipeline

• Graceful shutdown (closes #5): @app.on_event("shutdown") now
  cancels in-flight runner tasks and transitions papers to paused.
  Skips state.json-says-completed papers. Stops the "zombie row at
  designing/revision after every uvicorn restart" failure mode.
• Resume writes terminal status (closes #6): when resume runs on a
  paper whose state.json already has every stage complete, the runner
  now mirrors state.last_status back to the DB before returning.
  Previously the DB row stayed at designing (the entry value).
• Resume accepts zombies (closes #7): /api/papers/{id}/resume no
  longer requires status to be paused/failed. Any non-terminal
  status with no live runner task in _RUNNING is resumable. Combined
  with #5, this removes the manual-UPDATE workaround entirely.
• SQLite translation extensions (closes nothing — caught by live
  SQLite smoke after v0.4.0 shipped, fixed before tagging):
  NOW() → CURRENT_TIMESTAMP, plus ::int/::bigint/::numeric/
  ::float casts stripped alongside the existing type/json/interval
  casts. Without these, status UPDATEs silently failed and usage
  aggregations crashed SQLite with "unrecognized token: ':'".

Tests

• tests/pipeline/integration/test_graceful_shutdown.py — 3 new.
• tests/pipeline/integration/test_resume_terminal_status.py — 1 new.
• tests/pipeline/integration/test_resume_api.py — 4 new + 1 rewritten.

Test count: 326 → 333.