feat(perception): gate cross-host graph with acknowledged source clocks

src/k1link/perception/streaming_continuity.py

@@ -62,7 +62,13 @@ class InputContinuity:
             raise StreamSuspended("input is waiting for resynchronization")
 
     def pause(self, reason: str) -> None:
-        if reason not in ("input-disconnected", "input-timeout", "source-gap", "worker-telemetry"):
+        if reason not in (
+            "input-disconnected",
+            "input-timeout",
+            "source-gap",
+            "worker-telemetry",
+            "source-clock",
+        ):
             raise ValueError("unknown recoverable pause reason")
         if self.phase != "waiting":
             self.pauses += 1