fix(perception): require joint clock readiness before source activation

tests/test_perception_source_clock.py

@@ -18,6 +18,37 @@ from k1link.perception.streaming_queue import StreamMailbox
 from k1link.perception.streaming_source_clock import SourceAnchor, SourceClockMonitor
 
 
+def test_responder_warms_without_source_admission_and_rejects_wide_start():
+    monitor = SourceClockMonitor("worker", 10**12)
+    wide = sample(outbound=20_000_000, inbound=20_000_000)
+    now = wide.local_receive_ns + 10**12 + 1_000_000
+    anchor = SourceAnchor(10**12, wide.local_receive_ns + 1_000_000_000)
+    response = monitor.observe(wide, now, anchor, False)
+    assert response.anchor is monitor.anchor is None and response.bounds.samples == 1
+    with pytest.raises(StreamSuspended):
+        monitor.observed(now)
+    narrow = sample(2)
+    now = narrow.local_receive_ns + 10**12 + 1_000_000
+    response = monitor.observe(narrow, now, None, False)
+    assert response.anchor is None and response.bounds.samples == 2
+    response.bounds.require(now)
+    with pytest.raises(StreamSuspended):
+        monitor.observed(now)  # Valid clock is not permission to start without an anchor.
+    third = sample(3)
+    now = third.local_receive_ns + 10**12 + 1_000_000
+    assert monitor.observe(third, now, anchor, False).anchor == anchor
+    assert monitor.observed(now)[1] < 5_000_000
+
+
+def test_end_before_start_is_terminal_without_inventing_a_source_timeline():
+    monitor = SourceClockMonitor("worker", 10**12)
+    first = sample()
+    state = monitor.observe(first, first.local_receive_ns + 10**12 + 1_000_000, None, True)
+    assert state.ended and state.anchor is None
+    with pytest.raises(StreamSuspended):
+        monitor.observed(state.bounds.measured_at_ns)
+
+
 def sample(number=1, outbound=1_000_000, inbound=2_000_000, offset=10**12):
     t1 = 10**16 + number * 100_000_000
     return ClockProbe(