Make loop lifecycle explicit

[chriswu727]

Summary

• persist an explicit fail-closed loop state, transition reason, and monotonic sequence across claims, recovery, pauses, cancellation, verification, and terminal outcomes
• extract transition, decision, context/history, dispatch, verification, and delegation policies while retaining the existing progress guard as the no-progress control
• expose the persisted lifecycle through the API and task UI, migrate legacy rows safely, and document the design in ADR 0011

Verification

• uv run pytest -q (513 tests)
• uv run ruff check app tests alembic
• uv run ruff format --check app tests alembic
• uv run mypy app
• pnpm lint
• pnpm typecheck
• pnpm test (33 web/desktop tests)
• pnpm build
• Alembic empty upgrade, downgrade, re-upgrade, plus 8-state legacy data migration
• deterministic HTTP Verified Completion benchmark: 1/1 solved, 0 false acceptances, 2 steps, 24 tokens, valid integrity and replay