fix(tools): limit cancellation guard to pre-execution

CHANGELOG.md

@@ -17,6 +17,8 @@
 
 - Cancelled tool calls refuse actions before execution and discard results that settle after cancellation.
 
+- Cancelled catalog queries refuse execution when their signal is already aborted.
+
 - Treat explicitly current, complete empty vessel coverage as a successful update,
   clearing obsolete contacts while retaining stale or incomplete snapshots.