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

templates/shared/actions/runner_list.tmpl

@@ -66,7 +66,10 @@
 			<tbody>
 				{{range .Runners}}
 					<tr>
-						<td><span class="ui label {{if .IsOnline}}green{{end}}">{{.StatusLocaleName ctx.Locale}}</span></td>
+						<td>
+							<span class="ui label {{if .IsOnline}}green{{end}}">{{.StatusLocaleName ctx.Locale}}</span>
+							{{if .IsDisabled}}<span class="ui grey label">{{ctx.Locale.Tr "actions.runners.disabled"}}</span>{{end}}
+						</td>
 						<td>{{.ID}}</td>
 						<td><p data-tooltip-content="{{.Description}}">{{.Name}}</p></td>
 						<td>{{if .Version}}{{.Version}}{{else}}{{ctx.Locale.Tr "unknown"}}{{end}}</td>