fix(lab): seal RAV004 spatial replay transport

tests/test_canonical_lab_spatial.py

@@ -3,14 +3,17 @@ from __future__ import annotations
 import numpy as np
 import pytest
 
+import k1link.sessions.canonical_lab_spatial as spatial_module
 from k1link.sessions.canonical_lab_spatial import (
-    _TimedPoints,
-    _TimedPoses,
     _bounded_local_slam,
-    _estimate_sensor_height,
+    _CanonicalSpatialIndex,
     _estimate_local_sensor_height,
+    _estimate_sensor_height,
     _gravity_stable_basis_map_from_body,
     _ground_origin_map,
+    _TimedPoints,
+    _TimedPoses,
+    canonical_lab_spatial_playback_points,
 )
 
 
@@ -127,3 +130,43 @@ def test_sensor_height_tracks_current_source_window_instead_of_fixed_mount() ->
     assert high == pytest.approx(1.05, abs=0.03)
     assert low_samples >= 3 and high_samples >= 3
     assert low_source == high_source == "local-source-cloud-ground-quantile-median"
+
+
+def test_playback_track_binds_sparse_map_increments_to_dense_camera_timeline(
+    tmp_path,
+    monkeypatch,
+) -> None:
+    recording = tmp_path / "recording.rrd"
+    recording.write_bytes(b"sealed")
+    points = _TimedPoints(
+        times_ns=(10, 20),
+        values=(
+            np.asarray([[1.0, 2.0, 3.0]], dtype=np.float32),
+            np.asarray([[4.0, 5.0, 6.0], [7.0, 8.0, 9.0]], dtype=np.float32),
+        ),
+    )
+    empty_poses = _TimedPoses(times_ns=(), translations=(), quaternions_xyzw=())
+    index = _CanonicalSpatialIndex(
+        points=points,
+        poses=empty_poses,
+        trajectories=_TimedPoints(times_ns=(), values=()),
+        sensor_height_m=0.4,
+        sensor_height_sample_count=0,
+        sensor_height_mad_m=0.0,
+    )
+    monkeypatch.setattr(spatial_module, "_load_index", lambda *_args: index)
+
+    track, offsets = canonical_lab_spatial_playback_points(
+        recording,
+        "a" * 64,
+        (10, 15, 20, 25),
+    )
+
+    assert offsets == (0, 1, 1, 3, 3)
+    assert track.tolist() == [
+        [1.0, 2.0, 3.0],
+        [4.0, 5.0, 6.0],
+        [7.0, 8.0, 9.0],
+    ]
+    assert track.dtype == np.dtype("<f4")
+    assert not track.flags.writeable