fix(engine): respect global pause in reviewer + stuck detector

Reviewer subprocesses were spawned via fn_review_spec / fn_review_step
even with globalPause on, because reviewer.ts had no pause awareness.
Stuck detector also kept running, treating pause-disposed sessions as
inactivity and re-queuing tasks. Pause-transition listeners only called
session.dispose(), which doesn't always interrupt an in-flight LLM
stream — letting reviewer spawns leak through after pause flipped.

- reviewer.ts: re-read settings, return UNAVAILABLE without spawning
  when globalPause/enginePaused is on.
- stuck-task-detector.ts: skip checkStuckTasks() while paused.
- triage.ts / executor.ts: call session.abort() before dispose() in the
  pause-transition listener to interrupt in-flight work.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/engine/src/triage.ts

@@ -494,6 +494,14 @@ export class TriageProcessor {
           );
           this.pauseAborted.add(taskId);
           this.options.stuckTaskDetector?.untrackTask(taskId);
+          // abort() interrupts any in-flight LLM stream / tool call;
+          // dispose() then releases session resources.
+          const sessionWithAbort = session as { abort?: () => Promise<void>; dispose: () => void };
+          if (typeof sessionWithAbort.abort === "function") {
+            void sessionWithAbort.abort().catch((err) => {
+              planLog.warn(`Failed to abort triage session for ${taskId}: ${err}`);
+            });
+          }
           session.dispose();
         }
       }