[AZ-894] [AZ-896] Add CSV-driven replay adapter + format docs

Replaces the tlog two-clock replay surface with a single-clock path
driven by the Derkachi-schema CSV. --imu is the new required CLI arg;
--tlog stays as a deprecated alias (warned + ignored when --imu set)
until AZ-895 deletes it.

* csv_ground_truth.py parses the 15-column schema, fails fast at
  startup on every documented schema fault (AC-5).
* CsvReplayFcAdapter slots into ReplayInputBundle.fc_adapter alongside
  the tlog sibling; mirrors Invariant-5 outbound wiring; inbound bus is
  intentionally a no-op since the loop reads CSV directly.
* _run_replay_loop branches on imu_csv_path, stamps
  VioOutput.emitted_at_ns from the CSV-derived frame_end_ns (AC-4),
  closing the AZ-848 two-clock surface for the new path.
* AZ-896 ships the operator-facing format spec at
  _docs/02_document/contracts/replay/csv_replay_format.md plus a
  20-row example CSV (AC-3 regression-locked).

Tests: 11 + 12 new unit tests, plus updates to AZ-401 import-boundary
and AZ-402 CLI suites. Full unit suite 2,327 passed / 86 skipped.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/unit/test_az402_replay_cli.py

@@ -57,6 +57,10 @@ def _required_files(tmp_path: Path, _calib_payload: dict[str, Any]) -> dict[str,
     video.write_bytes(b"\x00\x00\x00\x18ftypmp42")  # placeholder
     tlog = tmp_path / "flight.tlog"
     tlog.write_bytes(b"\x00")
+    imu_csv = tmp_path / "data_imu.csv"
+    # Minimal placeholder — the CLI only validates existence, parsing
+    # happens later inside the runtime loop.
+    imu_csv.write_text("placeholder", encoding="utf-8")
     output = tmp_path / "out.jsonl"
     calib = tmp_path / "calib.json"
     calib.write_text(json.dumps(_calib_payload))
@@ -67,6 +71,7 @@ def _required_files(tmp_path: Path, _calib_payload: dict[str, Any]) -> dict[str,
     return {
         "video": video,
         "tlog": tlog,
+        "imu": imu_csv,
         "output": output,
         "camera_calibration": calib,
         "config": config_yaml,
@@ -95,6 +100,7 @@ def _argv(files: dict[str, Path], **overrides: Any) -> list[str]:
     """Build a CLI argv from the required-files fixture + overrides."""
     base = {
         "--video": str(files["video"]),
+        "--imu": str(files["imu"]),
         "--tlog": str(files["tlog"]),
         "--output": str(files["output"]),
         "--camera-calibration": str(files["camera_calibration"]),
@@ -477,6 +483,7 @@ def test_ac10_console_script_runs_help() -> None:
     # Required-arg surface check
     for arg in (
         "--video",
+        "--imu",
         "--tlog",
         "--output",
         "--camera-calibration",