refactor(config): extract shared environment detection logic

[usernane]

Description

Environment detection logic is duplicated in both HandlerConfig and SecurityConfig. Should be extracted to a shared utility.

Implementation Details

• Create EnvironmentDetector class in WebFiori\Error\Config
• Move detection logic (checking APP_ENV, display_errors, PRODUCTION constant) to this class
• Update HandlerConfig and SecurityConfig to use EnvironmentDetector
• Consider caching the detected environment

Acceptance Criteria

• Single source of truth for environment detection
• No duplicated detection logic
• Both config classes use shared detector
• Existing tests still pass