Simplify and enhance language detection and file loading mechanism:
- Parse primary language from browser settings more accurately.
- Remove redundant scanning of language files.
- Load default English language file as a base.
- Add support for region-specific language files if available.
- Remove unused language strings from various translation files.
These changes enhance the robustness and efficiency of language handling, ensuring better support for user language preferences.
Updated browser language detection to handle full locale strings and
mapped various Chinese variants to simplified or traditional Chinese.
Renamed language files for consistency with the new alias system.
This improves support for a wider array of language settings, ensuring
users receive content in their preferred language variant when possible.