feat(i18n): add locale-based language support

[mehmetseyfi]

✨ i18n / Locale Language Support

This PR introduces locale-based internationalization (i18n) support to the project.

🔧 How It Works

Language resolution follows this priority order:

1. If config.language is set → force that language
2. Otherwise → use .env LANG
3. If not available → fallback to en

export const t = initLocale(config?.language);

🧠 Features

• Automatic language detection via LANG environment variable
• Safe fallback to en
• Nested key support (modules.powermenu.sleep)
• String reference resolution ({common.noMatch})
• Parameter interpolation ({value}, {name}, etc.)
• Depth limit to prevent infinite reference loops

📌 Example

t("weather.feelsLike", { value: 24, unit: "°C" });
// → "Feels like 24°C"

📁 Changes

• Added i18n core under src/lib/locales
• Defined locale dictionary structure
• Exported a global t() helper

✅ Backward Compatibility

• Automatically falls back to en if locale is missing
• Does not break existing behavior