- Replaced legacy `api-keys` field with `auth.providers` in configuration, supporting multiple authentication providers including `config-api-key`.
- Added synchronization to maintain compatibility with legacy `api-keys`.
- Updated core components like request handling and middleware to use the new provider system.
- Enhanced management API endpoints for seamless integration with `auth.providers`.
- Renamed constants from uppercase to CamelCase for consistency.
- Replaced redundant file-based auth handling logic with the new `util.CountAuthFiles` helper.
- Fixed various error-handling inconsistencies and enhanced robustness in file operations.
- Streamlined auth client reload logic in server and watcher components.
- Applied minor code readability improvements across multiple packages.