[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>

_docs/_autodev_state.md

@@ -6,9 +6,9 @@ step: 10
 name: Implement
 status: in_progress
 sub_step:
-  phase: 0
-  name: awaiting-invocation
-  detail: ""
+  phase: 7
+  name: batch-loop
+  detail: "batch 3 of 4 — AZ-895"
 retry_count: 0
 cycle: 4
 tracker: jira