- Introduced `admin_handlers.go` to handle database creation requests via HTTP, including validation and response handling.
- Implemented `db_metadata.go` to manage database metadata caching and synchronization with a pubsub subscriber.
- Updated `gateway.go` to initialize the metadata cache and start the metadata subscriber in the background.
- Added new route for database creation in `routes.go` to expose the new functionality.
- Enhanced cluster management to support system database auto-joining and improved metadata handling for database operations.
