[josevictoremiliano]

Summary

Add Brazilian Portuguese and English interface translations, while preserving Simplified Chinese, using a dependency-free internationalization layer.

• Add 648 messages per locale (zh-CN, pt-BR, en) with consistent interpolation placeholders.
• Add a persisted language selector in Settings, including automatic Windows locale detection and English fallback for unsupported system languages.
• Localize the main interface, app-window controls, tray menus, native dialogs, resource profile summary and installer strings.
• Retain the Portuguese Electron locale and allow settings controls to wrap for longer translations.
• Document translation maintenance and add catalog checks, isolated Electron UI tests and a reproducible lightweight local test installer.

Validation

• npm test: 115 tests passed; optional real-APK fixture coverage was skipped because no fixture was supplied.
• npm run test:i18n: all 648 messages across three catalogs validated, including placeholders, locale selection, profile summaries and renderer behavior.
• Isolated Electron UI tests passed in Portuguese, English and Chinese, including language persistence across reloads, settings layout and app-launch feedback with mocked APIs. The packaged interface passed the same tests.
• Built the Windows x64 test installer 0.4.2-i18n.1; verified all packaged source files match the working tree.
• Contributor installed and manually tested the local build and reported it working.

Scope and limitations

App names, package names, paths, upstream release notes and raw runtime logs are preserved. Some diagnostics from internal runtime components still use Chinese. Automated UI tests use mocked Android APIs; they do not validate real Android app startup.

The lightweight test installer reuses existing runtime data or downloads missing components on demand. No installer binary, Android image or public release is included in this PR, and the project's release version is unchanged.