[houko]

Summary

The READMEs mixed languages: the English, Japanese, Korean and Traditional Chinese ones quoted Simplified Chinese UI labels and all five showed the same Chinese screenshots. The root cause was the app itself: every interface string was hard-coded Simplified Chinese, and the existing Interface language switch (English / 简体中文) only changed MyGo's own controls.

This moves the whole interface into MyGo's message catalogs and ships it in five languages, then rewrites each README in its own language with its own screenshots.

Interface

• 755 messages in apps/kando/locales/{en,zh-Hans,zh-Hant,ja,ko}.json (en is the catalog source), called through the generated locales.Xxx(...) functions. zh-Hans is the previous text byte for byte, so the Chinese interface is unchanged.
• Settings › General › Interface language offers all five, each named in itself; the window switches at once. Simplified Chinese stays the default.
• Text is produced when it is drawn, so a language change applies to everything on screen, including states found earlier (the sidebar status line, upload and connection-test results, the palette's answer cards).
• Shortcut groups are now IDs (groupPlayback, groupHelp, …) with localized titles, since the same strings were used to order and build the menu bar.
• Data is not translated: target languages stored in settings.json and library.json, font family values, prompts sent to the model, and patterns matched against yt-dlp's output stay as they are and are mapped to localized names where shown. One function (subtitle.TargetLanguageName) names a target language on every screen.
• packages/core and packages/media no longer carry UI text: site names (core.Link.Site is now an ID, named by films/sitename), whisper model blurbs and yt-dlp update hints moved into the app.
• Feedback issues opened on GitHub stay in Simplified Chinese whatever the interface language (feedbackIssueLanguage), so the maintainers' issues share one set of headings; the dialog itself is localized.
• Tests pin zh-Hans in each package's TestMain (locales/testlocale), so the existing assertions are untouched; every area adds an English test (TestSettingsInEnglish, TestPlayerInEnglish, …). locales/catalog_test.go requires every message in all five catalogs.
• AGENTS.md gains the rule for adding interface text.

READMEs and screenshots

• Each README quotes the labels of its own interface language and shows docs/assets/<language>/ pictures.
• KANDO_SCREENSHOTS_LANG renders the screenshot scenes in a given language, with a demo library for that reader (library names, film titles, and subtitles translated into the reader's language; English shows Spanish subtitles). TestScreenshotsReadme renders the four README pictures.
• The Chinese README no longer mixes in English terms (token, client id, inode, …).

Fixes found along the way

• Upload: the "video file is missing" error never showed, because BeginUpload stored the bare path while UploadView compared it with uploadMemo (kind + path). Regression test TestUploadSaysTheVideoIsMissing.
• The library's Local Video pill was a fixed 104 pt and cut longer labels; it now grows with its label.
• Connection-test results compared against the Chinese text "连接成功", which would have shown a passed test as an error after a language change.

Screenshots

Before: the English README showed the Chinese interface.

After: the library in English, Japanese, Korean and Traditional Chinese.

The player in English, and Settings › General before and after.

Notes for review

• Translations into zh-Hant, ja and ko were written without a native reviewer; a pass by native speakers is worth doing, especially for menu items, which follow Apple's wording.
• MyGo ships its own control strings for ja, zh-Hans and zh-Hant but not ko, so in Korean a few MyGo-provided texts (for example standard panel buttons) fall back to English.
• Messages produced at the moment of an event (message-bar notices, save errors, the 1.4 s player flash) keep the language they were produced in until the next one.

Test plan

• gofmt -l, go vet ./..., go tool mygo vet ., go tool mygo i18n check . (755 messages in 5 languages)
• CGO_ENABLED=0 go test ./packages/core/... ./packages/media/... ./apps/kando/...
• go tool mygo build apps/kando: the bundle declares en, ja, ko, zh-Hans, zh-Hant
• KANDO_SCREENSHOTS=… KANDO_SCREENSHOTS_LANG=<lang> go test ./apps/kando -run TestScreenshotsReadme for all five languages
• Not exercised by hand in the running app