[AZ-335] C1 warm-start hint persistence + F8 reboot recovery wiring

Adds JsonSidecarWarmStartHintStore (atomic JSON + SHA-256 sidecar via
AZ-280) inside c1_vio, plus the cross-strategy WarmStartWiredStrategy
wrapper + prime_warm_start_from_disk / prime_warm_start_from_fc hooks
at runtime_root. AC-7 post-reset covariance inflation and AC-8 "no
fake confidence" baseline floor are enforced at the wiring layer so
no strategy module needed edits. Adds three c1_vio config fields
(warm_start_store_dir, warm_start_save_period_frames,
post_reset_covariance_inflation_factor) and registers the new FDR
kind vio.warm_start. 34 unit tests cover all 10 ACs + 3 NFRs.

Verdict PASS_WITH_WARNINGS — see
_docs/03_implementation/reviews/batch_56_review.md for the four
non-blocking documentation findings (F1 cold-start log kind shorthand,
F2 strategy-frame pose semantics, F3 dev-hardware perf smoke, F4
runtime_root importing c1-internal _facade_spine for shared FDR
conventions).

Closes AZ-335; depends on AZ-528 (batch 55).

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

src/gps_denied_onboard/fdr_client/records.py

@@ -47,6 +47,28 @@ KNOWN_PAYLOAD_KEYS: Final[dict[str, frozenset[str]]] = {
     "vio.health": frozenset(
         {"state", "consecutive_lost", "bias_norm", "strategy_label", "frame_id"}
     ),
+    # AZ-335 / E-C1: emitted by the warm-start wiring on every successful
+    # `prime_warm_start_*` invocation (F2 takeoff load, F8 reboot reload,
+    # cold-start fall-through). Exactly ONE record per prime call.
+    # `source` is one of "f2_takeoff_fc" | "f8_reboot_disk" |
+    # "cold_start_no_hint" — distinguishes the three runtime paths so
+    # post-flight forensics can answer "did this flight reuse a prior
+    # hint?". `bias_norm` is the L2 norm of the loaded hint's accel||gyro
+    # bias (None on cold start, since there is no hint). `staleness_ns`
+    # is the monotonic-ns delta between hint capture and prime time
+    # (None on cold start). `pre_reboot_covariance_norm` is the AC-8
+    # baseline carried alongside the hint on the F8 path (None on F2
+    # and cold start, since the wiring's covariance floor is only
+    # enforced on the F8 reload path).
+    "vio.warm_start": frozenset(
+        {
+            "source",
+            "strategy_label",
+            "bias_norm",
+            "staleness_ns",
+            "pre_reboot_covariance_norm",
+        }
+    ),
     "state.tick": frozenset({"frame_id", "fused_pose", "covariance_2x2", "estimator_label"}),
     "tile_match": frozenset({"frame_id", "tile_id", "score", "match_count", "ransac_inliers"}),
     "overrun": frozenset({"producer_id", "dropped_count"}),