fix(lab): seal RAV004 spatial replay transport

tests/test_vegetation_shadow_lab.py

@@ -22,6 +22,7 @@ from k1link.laboratory.evidence_report import verify_laboratory_evidence_result
 from k1link.laboratory.vegetation_policy_review import seal_vegetation_policy_review
 from k1link.laboratory.vegetation_shadow_lab import seal_vegetation_shadow_lab
 from k1link.web.vegetation_shadow_lab_api import (
+    _canonical_route_playback_chunk_descriptor,
     _mask_component_boxes,
     _route_tgs_anchor_payload,
     build_vegetation_shadow_lab_router,
@@ -42,6 +43,25 @@ def test_semantic_component_boxes_keep_distinct_objects_separate() -> None:
     ]
 
 
+def test_route_playback_chunk_descriptor_seals_only_requested_binary_window() -> None:
+    points = np.arange(18, dtype="<f4").reshape(6, 3)
+    descriptor = _canonical_route_playback_chunk_descriptor(
+        "/api/v1/laboratory/vegetation-shadow",
+        f"lab-v1-vegetation-shadow-{'a' * 64}",
+        memoryview(points).cast("B"),
+        (0, 1, 1, 3, 6),
+        0,
+    )
+
+    assert descriptor is not None
+    assert descriptor["start"] == 0
+    assert descriptor["count"] == 4
+    assert descriptor["point_count"] == 6
+    assert descriptor["bytes"] == points.nbytes
+    assert descriptor["shape"] == [6, 3]
+    assert len(str(descriptor["sha256"])) == 64
+
+
 def test_route_tgs_anchor_payload_preserves_metric_evidence(tmp_path: Path) -> None:
     path = tmp_path / "tgs-evidence.npz"
     point_counts = np.arange(1, 11, dtype=np.int64)