release(v1.8.0): feat(onlyoffice): first-class ONLYOFFICE integration (view/edit), admin UI, API, CSP helpers

Refs #37 — implements ONLYOFFICE integration suggested in the discussion; video progress saving will be tracked separately.

public/api/onlyoffice/status.php

@@ -0,0 +1,13 @@
+<?php
+/**
+ * @OA\Get(
+ *   path="/api/onlyoffice/status.php",
+ *   summary="ONLYOFFICE availability & supported extensions",
+ *   tags={"ONLYOFFICE"},
+ *   @OA\Response(response=200, description="Status JSON")
+ * )
+ */
+declare(strict_types=1);
+require_once __DIR__ . '/../../../config/config.php';
+require_once PROJECT_ROOT . '/src/controllers/OnlyOfficeController.php';
+(new OnlyOfficeController())->status();