Expire stuck plugin jobs (#8492)

* Add stale job expiry and expire API

* Add expire job button

* Add test hook and coverage for ExpirePluginJobAPI

* Document scheduler filtering side effect and reuse helper

* Restore job spec proposal test

* Regenerate plugin template output

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Co-authored-by: Copilot <copilot@github.com>

weed/admin/dash/admin_server.go

@@ -98,6 +98,7 @@ type AdminServer struct {
 	// Maintenance system
 	maintenanceManager *maintenance.MaintenanceManager
 	plugin             *adminplugin.Plugin
+	expireJobHandler   func(jobID string, reason string) (*adminplugin.TrackedJob, bool, error)
 
 	// Topic retention purger
 	topicRetentionPurger *TopicRetentionPurger
@@ -1020,6 +1021,17 @@ func (s *AdminServer) GetPluginJobDetail(jobID string, activityLimit, relatedLim
 	return s.plugin.BuildJobDetail(jobID, activityLimit, relatedLimit)
 }
 
+// ExpirePluginJob marks an active plugin job as failed so it no longer blocks scheduling.
+func (s *AdminServer) ExpirePluginJob(jobID, reason string) (*adminplugin.TrackedJob, bool, error) {
+	if handler := s.expireJobHandler; handler != nil {
+		return handler(jobID, reason)
+	}
+	if s.plugin == nil {
+		return nil, false, fmt.Errorf("plugin is not enabled")
+	}
+	return s.plugin.ExpireJob(jobID, reason)
+}
+
 // ListPluginActivities returns plugin job activities for monitoring.
 func (s *AdminServer) ListPluginActivities(jobType string, limit int) []adminplugin.JobActivity {
 	if s.plugin == nil {