Refactor: Move v2 database metadata schema creation to async Database worker

### TL;DR In [`Create.php`](https://github.com/appwrite/appwrite/blob/a6d30130ba04e436ec46b8de4138af523079a8a2/src/Appwrite/Platform/Modules/Databases/Http/Databases/Create.php#L37-L38), there is a TODO to move the v2 metadata schema creation to the `Databases` background worker. Currently, the metadata collection (`database_{sequence}`) is created **synchronously** inside the HTTP request ([line 204](https://github.com/appwrite/appwrite/blob/a6d30130ba04e436ec46b8de4138af523079a8a2/src/Appwrite/Platform/Modules/Databases/Http/Databases/Create.php#L204)), blocking the API response until the DDL operation completes. This is inconsistent with how Collections, Attributes, and Indexes are handled (all async via workers). --- ### Detailed Context **The TODO (line 37-38):** ```php // TODO: use database worker for for creating the v2 schema if not present // it is considered that the v2 metadata schema is already created during server start in the http.php ``` > [Source permalink](https://github.com/appwrite/appwrite/blob/a6d30130ba04e436ec46b8de4138af523079a8a2/src/Appwrite/Platform/Modules/Databases/Http/Databases/Create.php#L37-L38) **The synchronous call (line 204):** ```php $this->createMetadataCollection($dbForProject, $database); ``` > [Source permalink](https://github.com/appwrite/appwrite/blob/a6d30130ba04e436ec46b8de4138af523079a8a2/src/Appwrite/Platform/Modules/Databases/Http/Databases/Create.php#L204) **What happens today:** 1. User hits `POST /v1/databases`. 2. A document is saved to the `databases` collection. 3. `createMetadataCollection()` runs **synchronously** — it executes a DDL query (`createCollection`) on the project database, blocking the HTTP response. 4. It also **assumes** the target database cluster already has the base Utopia "v2 schema" initialized from the `http.php` boot script. **Why this is a problem:** - **API Latency:** DDL I/O blocks the response. Every other schema operation (attributes, indexes, collections) is already async via worker…