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

modules/structs/repo_actions.go

@@ -196,10 +196,18 @@ type ActionRunner struct {
 	Name      string               `json:"name"`
 	Status    string               `json:"status"`
 	Busy      bool                 `json:"busy"`
+	Disabled  bool                 `json:"disabled"`
 	Ephemeral bool                 `json:"ephemeral"`
 	Labels    []*ActionRunnerLabel `json:"labels"`
 }
 
+// EditActionRunnerOption represents the editable fields for a runner.
+// swagger:model
+type EditActionRunnerOption struct {
+	// required: true
+	Disabled *bool `json:"disabled"`
+}
+
 // ActionRunnersResponse returns Runners
 type ActionRunnersResponse struct {
 	Entries    []*ActionRunner `json:"runners"`