fix: expose summaryStored in session status to detect silent summary loss (#1633)

Stop hook polled queueLength===0 as a proxy for summary success, but the queue
empties regardless of whether the LLM produced valid <summary> tags. Added
lastSummaryStored tracking on ActiveSession, surfaced via the /api/sessions/status
endpoint, and emit a logger.warn in the Stop hook when summaryStored===false.

Generated by Claude Code
Vibe coded by ousamabenyounes

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

src/services/worker/http/routes/SessionRoutes.ts

@@ -672,6 +672,9 @@ export class SessionRoutes extends BaseRouteHandler {
       status: 'active',
       sessionDbId,
       queueLength,
+      // Expose whether the last storage operation included a summary record.
+      // The Stop hook uses this to detect silent summary loss when the queue empties (#1633).
+      summaryStored: session.lastSummaryStored ?? null,
       uptime: Date.now() - session.startTime
     });
   });