fix(k1): stabilize repeated acquisition and live viewer recovery

tests/test_live_perception.py

@@ -136,6 +136,31 @@ def test_live_ingress_allows_only_one_worker_consumer() -> None:
     ingress.open_consumer("worker-2")
 
 
+def test_live_ingress_new_session_discards_queued_events_from_previous_session() -> None:
+    ingress = LivePerceptionIngress()
+    ingress.open_consumer("worker-1")
+    ingress.begin_session("session-1")
+    assert ingress.publish(
+        modality="lidar",
+        source_id="lixel/application/report/lio_pcl",
+        source_sequence=1,
+        captured_at_epoch_ns=1,
+        received_monotonic_ns=1,
+        payload=b"old-session",
+    )
+
+    ingress.end_session("session-1")
+    ingress.begin_session("session-2")
+
+    events = []
+    while (event := ingress.take_next("worker-1", timeout=0)) is not None:
+        events.append(event)
+    assert len(events) == 1
+    assert events[0].session_id == "session-2"
+    assert events[0].modality == "control"
+    assert events[0].payload == b'{"event":"session-start"}'
+
+
 def test_live_result_round_trip_keeps_video_mask_boxes_and_shadow_authority() -> None:
     mask = np.zeros((600, 800), dtype=np.uint8)
     mask[100:120, 200:240] = 4