Add an i18n module (eve.I18n) for game localization:
- Load per-language JSON locale tables from VFS or raw JSON.
- Dot-path key lookup with {name} placeholder substitution.
- CLDR-style plural rules (en/fr/ru/pl/cs/zh and more).
- Fall back to default language, then to the raw key.
- Optional file auto-reload via update(dt).
Self-contained JSON parser (no Poco) so it builds on WASM too.
Includes C++ + Squirrel script tests, user/module docs, an
examples/i18n demo, and i18n integration in the dialogue example.
