refactor(monitoring): consolidate workers and extract to scheduler process

Remove standalone lease-recovery, received-inspection, and result-recovery
workers from tenant-api (now handled by scheduler process). Add configurable
concurrency to ingest and projection-rebuild workers via MonitoringWorkers
runtime config. Extract shared runtime types for worker configuration.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/internal/tenant/app/monitoring_received_inspection.go

@@ -23,6 +23,8 @@ type monitoringStaleReceivedTask struct {
 	CallbackReceivedAt time.Time
 }
 
+type MonitoringStaleReceivedTask = monitoringStaleReceivedTask
+
 func markMonitoringStaleReceivedTasks(ctx context.Context, tx pgx.Tx, now time.Time, threshold time.Duration, limit int) ([]monitoringStaleReceivedTask, error) {
 	if limit <= 0 {
 		limit = defaultMonitoringReceivedInspectLimit
@@ -111,3 +113,11 @@ func markMonitoringStaleReceivedTasks(ctx context.Context, tx pgx.Tx, now time.T
 
 	return result, nil
 }
+
+func MarkMonitoringStaleReceivedTasks(ctx context.Context, tx pgx.Tx, now time.Time, threshold time.Duration, limit int) ([]MonitoringStaleReceivedTask, error) {
+	items, err := markMonitoringStaleReceivedTasks(ctx, tx, now, threshold, limit)
+	if err != nil {
+		return nil, err
+	}
+	return items, nil
+}