feat: Implement runner execution pipeline with planner dispatch and execution services

- Introduced RunnerBackgroundService to handle execution of runner segments.
- Added RunnerExecutionService for processing segments and aggregating results.
- Implemented PlannerQueueDispatchService to manage dispatching of planner messages.
- Created PlannerQueueDispatcherBackgroundService for leasing and processing planner queue messages.
- Developed ScannerReportClient for interacting with the scanner service.
- Enhanced observability with SchedulerWorkerMetrics for tracking planner and runner performance.
- Added comprehensive documentation for the new runner execution pipeline and observability metrics.
- Implemented event emission for rescan activity and scanner report readiness.

deploy/compose/docker-compose.prod.yaml

@@ -193,6 +193,26 @@ services:
       - stellaops
     labels: *release-labels
 
+  scheduler-worker:
+    image: registry.stella-ops.org/stellaops/scheduler-worker:2025.10.0-edge
+    restart: unless-stopped
+    depends_on:
+      - mongo
+      - nats
+      - scanner-web
+    command:
+      - "dotnet"
+      - "StellaOps.Scheduler.Worker.Host.dll"
+    environment:
+      SCHEDULER__QUEUE__KIND: "${SCHEDULER_QUEUE_KIND:-Nats}"
+      SCHEDULER__QUEUE__NATS__URL: "${SCHEDULER_QUEUE_NATS_URL:-nats://nats:4222}"
+      SCHEDULER__STORAGE__CONNECTIONSTRING: "mongodb://${MONGO_INITDB_ROOT_USERNAME}:${MONGO_INITDB_ROOT_PASSWORD}@mongo:27017"
+      SCHEDULER__STORAGE__DATABASE: "${SCHEDULER_STORAGE_DATABASE:-stellaops_scheduler}"
+      SCHEDULER__WORKER__RUNNER__SCANNER__BASEADDRESS: "${SCHEDULER_SCANNER_BASEADDRESS:-http://scanner-web:8444}"
+    networks:
+      - stellaops
+    labels: *release-labels
+
   notify-web:
     image: ${NOTIFY_WEB_IMAGE:-registry.stella-ops.org/stellaops/notify-web:2025.09.2}
     restart: unless-stopped