Feature: Add per-runner “Disable/Pause” (#36776)

This PR adds per-runner disable/enable support for Gitea Actions so a
registered runner can be paused from picking up new jobs without
unregistering.

Disabled runners stay registered and online but are excluded from new
task assignment; running tasks are allowed to finish. Re-enabling
restores pickup, and runner list/get responses now expose disabled
state.

Also added an endpoint for testing
http://localhost:3000/devtest/runner-edit/enable

<img width="1509" height="701" alt="Bildschirmfoto 2026-02-27 um 22 13
24"
src="https://github.com/user-attachments/assets/5328eda9-e59c-46b6-b398-f436e50ee3da"
/>


Fixes: https://github.com/go-gitea/gitea/issues/36767

routers/api/actions/runner/runner.go

@@ -156,10 +156,16 @@ func (s *Service) FetchTask(
 	}
 
 	if tasksVersion != latestVersion {
+		// Re-load runner from DB so task assignment uses current IsDisabled state
+		// (avoids race where disable commits while this request still has stale runner).
+		freshRunner, err := actions_model.GetRunnerByUUID(ctx, runner.UUID)
+		if err != nil {
+			return nil, status.Errorf(codes.Internal, "get runner: %v", err)
+		}
 		// if the task version in request is not equal to the version in db,
 		// it means there may still be some tasks that haven't been assigned.
 		// try to pick a task for the runner that send the request.
-		if t, ok, err := actions_service.PickTask(ctx, runner); err != nil {
+		if t, ok, err := actions_service.PickTask(ctx, freshRunner); err != nil {
 			log.Error("pick task failed: %v", err)
 			return nil, status.Errorf(codes.Internal, "pick task: %v", err)
 		} else if ok {