fix(upgrade): wait for new version before showing success

Expose the running Coolify version on /api/health and only treat an upgrade as complete once that version meets the target. Parse upgrade status in a shared service, start the update after the Livewire response, and keep polling when the instance is still on the old version.

app/Http/Controllers/Api/OtherController.php

@@ -292,13 +292,20 @@ class OtherController extends Controller
 
     #[OA\Get(
         summary: 'Healthcheck',
-        description: 'Healthcheck endpoint.',
+        description: 'Healthcheck endpoint. Includes the running Coolify version in the X-Coolify-Version header.',
         path: '/health',
         operationId: 'healthcheck',
         responses: [
             new OA\Response(
                 response: 200,
                 description: 'Healthcheck endpoint.',
+                headers: [
+                    new OA\Header(
+                        header: 'X-Coolify-Version',
+                        description: 'Currently running Coolify version.',
+                        schema: new OA\Schema(type: 'string', example: '4.3.1'),
+                    ),
+                ],
                 content: new OA\MediaType(
                     mediaType: 'text/html',
                     schema: new OA\Schema(type: 'string'),
@@ -316,6 +323,6 @@ class OtherController extends Controller
     )]
     public function healthcheck(Request $request)
     {
-        return 'OK';
+        return response('OK')->header('X-Coolify-Version', (string) config('constants.coolify.version'));
     }
 }