feat: app-to-app integration framework + OnlyOffice handlers

Generic integration system for connecting deployed apps via toggle UI.
First handlers: OnlyOffice→FileBrowser (config.yaml patch) and
OnlyOffice→Nextcloud (occ CLI). Lifecycle hooks auto-suspend on
stop and re-apply on start.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

controller/internal/web/templates/app_info.html

@@ -179,6 +179,67 @@ async function saveOptionalConfig(stackName) {
 </script>
 {{end}}
 
+{{if .HasIntegrations}}
+<div class="app-optional-config">
+    <h3>Integrációk</h3>
+    <p class="config-group-desc">
+        Más telepített alkalmazásokkal való összekapcsolás. Az integráció automatikusan felfüggesztődik, ha bármelyik alkalmazás leáll, és újraaktiválódik indításkor.
+    </p>
+
+    {{range .Integrations}}
+    <div class="config-field" style="display:flex;align-items:center;justify-content:space-between;gap:1rem;padding:.75rem 0;border-bottom:1px solid var(--border)">
+        <div style="flex:1">
+            <strong>{{.Label}}</strong>
+            <p class="config-field-help" style="margin:0">{{.Description}}</p>
+            {{if not .TargetDeployed}}
+                <span class="badge badge-muted" style="margin-top:.25rem;display:inline-block">Nincs telepítve</span>
+            {{else if not .TargetRunning}}
+                <span class="badge badge-orphaned" style="margin-top:.25rem;display:inline-block">Célalkalmazás leállítva</span>
+            {{else if eq .Status "error"}}
+                <span class="badge badge-orphaned" style="margin-top:.25rem;display:inline-block">Hiba</span>
+            {{else if .Enabled}}
+                <span class="badge badge-ok" style="margin-top:.25rem;display:inline-block">Aktív</span>
+            {{end}}
+        </div>
+        <label class="toggle">
+            <input type="checkbox"
+                   {{if .Enabled}}checked{{end}}
+                   {{if not .TargetDeployed}}disabled title="A célalkalmazás nincs telepítve"{{end}}
+                   {{if and .TargetDeployed (not .TargetRunning)}}disabled title="A célalkalmazás nem fut"{{end}}
+                   onchange="toggleIntegration('{{$.Stack.Name}}', '{{.Target}}', this.checked, this)">
+            <span class="toggle-label"></span>
+        </label>
+    </div>
+    {{end}}
+</div>
+
+<script>
+async function toggleIntegration(provider, target, enable, checkbox) {
+    checkbox.disabled = true;
+    try {
+        var resp = await fetch('/api/integrations/' + provider + '/' + target, {
+            method: 'POST',
+            headers: Object.assign({'Content-Type': 'application/json'}, csrfHeaders()),
+            body: JSON.stringify({enable: enable})
+        });
+        var data = await resp.json();
+        if (!data.ok) {
+            checkbox.checked = !enable;
+            alert(data.error || 'Hiba történt');
+        } else {
+            // Reload to update status badges
+            setTimeout(function(){ location.reload(); }, 500);
+            return;
+        }
+    } catch(err) {
+        checkbox.checked = !enable;
+        alert('Hálózati hiba');
+    }
+    checkbox.disabled = false;
+}
+</script>
+{{end}}
+
 {{if .GeoGlobalEnabled}}
 <div class="app-optional-config">
     <h3>Földrajzi korlátozás</h3>