fix: self-healing claimNextMessage prevents stuck processing messages (#1159)

* fix: self-healing claimNextMessage prevents stuck processing messages

claimAndDelete → claimNextMessage with atomic self-healing: resets stale
processing messages (>60s) back to pending before claiming. Eliminates
stuck messages from generator crashes without external timers. Removes
redundant idle-timeout reset in worker-service.ts. Adds QUEUE to logger
Component type.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: update stale comments in SessionQueueProcessor to reflect claim-confirm pattern

Comments still referenced the old claim-and-delete pattern after the
claimNextMessage rename. Updated to accurately describe the current
lifecycle where messages are marked as processing and stay in DB until
confirmProcessed() is called.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: move Date.now() inside transaction and extract stale threshold constant

- Move Date.now() inside claimNextMessage transaction closure so timestamp
  is fresh if WAL contention causes retry
- Extract STALE_PROCESSING_THRESHOLD_MS to module-level constant
- Add comment clarifying strict < boundary semantics

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

src/services/worker-service.ts

@@ -614,17 +614,16 @@ export class WorkerService {
           return;
         }
 
-        // Shared store for idle-reset and pending-count checks below
+        // Store for pending-count check below
         const { PendingMessageStore } = require('./sqlite/PendingMessageStore.js');
         const pendingStore = new PendingMessageStore(this.dbManager.getSessionStore().db, 3);
 
         // Idle timeout means no new work arrived for 3 minutes - don't restart
+        // No need to reset stale processing messages here — claimNextMessage() self-heals
         if (session.idleTimedOut) {
           logger.info('SYSTEM', 'Generator exited due to idle timeout, not restarting', {
             sessionId: session.sessionDbId
           });
-          // Reset stale processing messages so they can be picked up later
-          pendingStore.resetStaleProcessingMessages(0, session.sessionDbId); // Reset this session's messages only
           session.idleTimedOut = false; // Reset flag
           this.broadcastProcessingStatus();
           return;