T12: OpenClaw Lane B sweep hermetic smoke (quiesce + dedupe)

[philcunliffe]

Summary

• New backfill_openclaw_fixture hermetic smoke under hypaware-core/smoke/flows, mirroring backfill_claude_fixture.js / backfill_codex_fixture.js: writes a minimal OpenClaw v3 session JSONL in the nested-message-envelope shape (PR OpenClaw backfill reads message fields one level too high, projecting 0 rows #552's reader) under a temp agents/<id>/sessions/ tree with a controllable mtime.
• Drives the real createBackfillSweepDriver (T9) through a cron-due tick and asserts:
  • (a) a file inside the default 180000ms quiesce window is skipped
  • (b) a file backdated past it is captured with native message identity
  • (c) rerunning the sweep on a later cron-due tick (fresh devRunId, forcing a genuine re-scan of committed partitions) nets zero new rows for the already-written part_ids
• Fixes a latent bug surfaced by driving a real, non-dry-run sweep write for the first time (T9's own tests only ever exercised a mocked runBackfill seam): writeRows/flushDataset read ctx.query, which BackfillRunnerContext never carried and the daemon's createBackfillSweepDriver(...) call never supplied, so any real sweep write crashed on Cannot read properties of undefined (reading 'getDataset'), in both the smoke and the real daemon path. Threaded query through BackfillRunnerContext, BackfillSweepDriverOptions, createBackfillSweepDriver, and the daemon's sweepDriver construction.
• Updated LLP 0172's field enumeration and ctx code samples (Sections 4.3/4.4) to match, and extended the existing T9 unit tests to cover the new required field.

Test plan

• npm run typecheck clean
• npm test (3276 passed, 1 skipped, 0 failed)
• npm run smoke -- backfill_openclaw_fixture ok
• npm run smoke -- backfill_claude_fixture ok (no regression)
• npm run smoke -- backfill_codex_fixture ok (no regression)
• npm run smoke -- daemon_foreground_start_stop ok (real daemon sweep-driver wiring)
• npm run smoke -- walkthrough_backfill_client_history ok (CLI/onboarding backfill path)

Task-Id: T12