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_errors.go

@@ -7,3 +7,7 @@ func monitoringInternalError(code int, message, detail string, cause error) *res
 	appErr.Cause = cause
 	return appErr
 }
+
+func InternalMonitoringError(code int, message, detail string, cause error) *response.AppError {
+	return monitoringInternalError(code, message, detail, cause)
+}