feat(perception): qualify 1x realtime replay envelope

tests/test_e15_shadow_runtime.py

@@ -46,13 +46,25 @@ def test_incremental_media_buffer_is_bounded_and_fail_closed() -> None:
         source.read(100)
 
 
-def test_persistent_decoder_rejects_camera_fragment_gaps_before_decode() -> None:
+def test_persistent_decoder_counts_latest_wins_camera_fragment_gaps() -> None:
     decoder = PersistentFmp4Decoder(on_frame=lambda _frame: None)
     decoder.start()
     decoder.feed_init(b"not-a-real-init")
     decoder.feed_segment(_metadata(1), b"first")
-    with pytest.raises(ShadowRuntimeError, match="sequence gap"):
-        decoder.feed_segment(_metadata(3), b"third")
+    decoder.feed_segment(_metadata(3), b"third")
+    assert decoder.snapshot()["source_sequence_gaps"] == 1
+    decoder.finish_input()
+    with pytest.raises(ShadowRuntimeError, match="decoder failed"):
+        decoder.join()
+
+
+def test_persistent_decoder_rejects_non_increasing_camera_sequence() -> None:
+    decoder = PersistentFmp4Decoder(on_frame=lambda _frame: None)
+    decoder.start()
+    decoder.feed_init(b"not-a-real-init")
+    decoder.feed_segment(_metadata(2), b"second")
+    with pytest.raises(ShadowRuntimeError, match="not increasing"):
+        decoder.feed_segment(_metadata(2), b"duplicate")
     decoder.finish_input()
     with pytest.raises(ShadowRuntimeError, match="decoder failed"):
         decoder.join()