# Replay: deprecate auto_sync surface; tlog adapter → audit-only

**Task**: AZ-895_deprecate_auto_sync_surface
**Name**: Remove the tlog+video auto-sync infrastructure and reframe `tlog_replay_adapter.py` as audit-only, now that AZ-894 ships the CSV-driven primary path
**Description**: User decision (2026-05-26): the test/demo replay path will accept a paired (video, CSV) input from the operator instead of auto-syncing a tlog and video. Auto-sync is unnecessary in production (single edge device, single clock by design) and over-engineered for test (the CSV already encodes the alignment).

**Complexity**: 2 SP
**Dependencies**: AZ-894 (must ship first — the CSV adapter is the replacement)
**Component**: replay_input (auto_sync.py, tlog_video_adapter.py), cli/replay, runtime_root/_replay_branch
**Tracker**: AZ-895 (https://denyspopov.atlassian.net/browse/AZ-895)
**Parent Epic**: (none — cycle-4 replay-input redesign)

## Touch list

- `src/gps_denied_onboard/replay_input/auto_sync.py` — delete or convert to a clear no-op that raises `ReplayInputAdapterError("auto-sync removed; supply --imu CSV instead")`
- `src/gps_denied_onboard/replay_input/tlog_video_adapter.py` — strip auto-sync invocations
- `src/gps_denied_onboard/cli/replay.py` — remove `--time-offset-ms` / `--skip-auto-sync-validation` flags (or mark deprecated with one-cycle warning)
- `src/gps_denied_onboard/runtime_root/_replay_branch.py` — strip auto-sync wiring
- `tests/unit/replay_input/test_az405_auto_sync.py` — pass against the new behaviour or delete with rationale recorded in the batch report
- `tests/e2e/replay/test_derkachi_real_tlog.py` — continues to `@xfail` with the AZ-848-scoped reason; nothing in this ticket fixes the underlying tlog-clock bug
- `tlog_replay_adapter.py` / `tlog_ground_truth.py` — module docstrings updated to call out the new audit-only / one-shot-export roles

## Acceptance Criteria

- **AC-1**: `auto_sync.py` is either deleted or made into a clear no-op that raises `ReplayInputAdapterError("auto-sync removed; supply --imu CSV instead")`.
- **AC-2**: All references to `--time-offset-ms` / `--skip-auto-sync-validation` flags in the CLI are removed or marked deprecated with a one-cycle deprecation warning.
- **AC-3**: `test_az405_auto_sync` tests either pass against the new behaviour or are deleted with rationale recorded in the batch report.
- **AC-4**: `test_derkachi_real_tlog.py` continues to `@xfail` with the AZ-848-scoped reason; nothing in this ticket fixes the underlying tlog-clock bug.
- **AC-5**: Module docstrings of `tlog_replay_adapter.py` and `tlog_ground_truth.py` are updated to call out their new audit-only / one-shot-export roles.

## Out of scope

- AZ-848 / AZ-883 structural fix — they stay open as backlog (tlog path is still broken, just no longer the primary path).
- New CSV export tooling for arbitrary tlogs — future ticket.

## References

- Cycle-3 retro: `_docs/06_metrics/retro_2026-05-26.md`
- Companion: AZ-894 (CSV adapter — must land first), AZ-896 (docs), AZ-897 (UI)
