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/helm/stellaops/values.yaml

@@ -34,4 +34,16 @@ telemetry:
       metricsPort: 9464
     resources: {}
 
-services: {}
+services:
+  scheduler-worker:
+    image: registry.stella-ops.org/stellaops/scheduler-worker:2025.10.0-edge
+    replicas: 1
+    command:
+      - dotnet
+      - StellaOps.Scheduler.Worker.Host.dll
+    env:
+      SCHEDULER__QUEUE__KIND: Nats
+      SCHEDULER__QUEUE__NATS__URL: nats://nats:4222
+      SCHEDULER__STORAGE__CONNECTIONSTRING: mongodb://scheduler-mongo:27017
+      SCHEDULER__STORAGE__DATABASE: stellaops_scheduler
+      SCHEDULER__WORKER__RUNNER__SCANNER__BASEADDRESS: http://scanner-web:8444