* Added a database factory function to allow reconnection when the database is closed.
* Implemented mutex locks for safe concurrent access to the database connection.
* Updated all database query methods to handle reconnection attempts on closed connections.
* Enhanced error handling for database operations across multiple providers.
* Introduce SQLNames struct to define stored procedure names.
* Update DatabaseAuthenticator, JWTAuthenticator, and other providers to use SQLNames for procedure calls.
* Remove hardcoded procedure names for better flexibility and customization.
* Implement validation for SQL names to ensure they are valid identifiers.
* Add tests for SQLNames functionality and merging behavior.
* Add error handling for JSON encoding and HTTP server calls.
* Update passkey examples to improve readability and maintainability.
* Ensure consistent use of error handling across all examples.
* Introduce OAuth2 authentication examples for Google, GitHub, and custom providers.
* Implement OAuth2 methods for handling authentication, token refresh, and logout.
* Create a flexible structure for supporting multiple OAuth2 providers.
* Enhance DatabaseAuthenticator to manage OAuth2 sessions and user creation.
* Add database schema setup for OAuth2 user and session management.
