Offer "Pseudo-English" (qps-ploc) as a UI language for i18n testing (BL-16748)

[andrew-polk]

Problem

We have no way to see which of Bloom's on-screen strings actually go through localization. A string someone hard-coded, a placeholder that got mangled, a label the layout clips once it grows — all of it looks perfectly fine in English, and only surfaces when a translator or a user in another language hits it.

What the PR does

On the developer and alpha channels, the UI Language menu now offers Pseudo-English (i18n test). L10NSharp 10.1.0-beta0001 pseudolocalizes every lookup for the standard qps-ploc pseudo-locale by transforming the live English at lookup time — each vowel doubled and accented, the whole string bracketed, so Title Missing becomes [Tîitlée Mîissîing]. A tester can then read the problems straight off the screen: plain English means the string was never internationalized, a visible {0} or %0 means a broken placeholder, a missing ] means truncation, brackets mid-sentence mean the sentence is concatenated at runtime, and clipped layout means we can't cope with the ~30–40% growth real translations bring. No qps-* translation files exist or are ever written.

• Program.SetUpLocalization turns the locale on for the developer and alpha channels only, and GetDesiredUiLanguage refuses a stored qps-ploc on a channel that doesn't offer it — otherwise a setting carried over from an alpha would leave a release user with a mangled UI and no menu entry to escape it.
• WorkspaceView names the locale itself (Palaso's language-name lookup has nothing useful to say about a pseudo-locale) and puts it last in the menu rather than sorting it among real languages.
• I18NApi pseudolocalizes the English fallback it returns for ids that aren't in the English XLIFF. Without this those come back as plain English and are indistinguishable from hard-coded text, which defeats the exercise.
• The locale is excluded from the two places where the list of available localizations feeds book data rather than the UI: the pre-translated content TranslationGroupManager writes into a new book, and the hint-bubble language chooser.
• DistFiles/localization/README.md documents that the locale is runtime-derived, that no qps-* XLF should ever exist, and which surfaces stay plain English on purpose (the whole-file localizations — template readmes, help pages, xmatter descriptions) so the tester's rule stays exact.
• Bloom's workspace tabs carry a data-workspace-tab attribute so automation can find them without matching the visible English label, which breaks under this locale and under any real localization.

Ref: https://issues.bloomlibrary.org/youtrack/issue/BL-16748

Devin review

---

This change is 

[greptile-apps]

Greptile Summary

Adds the L10NSharp qps-ploc pseudo-locale as a developer/alpha-only UI language for finding internationalization and layout defects.

• Gates pseudo-localization by release channel and normalizes carried-over settings to English on unsupported channels.
• Adds pseudo-locale naming, menu placement, and fallback-string transformation.
• Excludes the pseudo-locale from book-content translation generation and hint-language authoring.
• Adds language-independent workspace-tab automation selectors, documentation, and focused tests.

Important Files Changed

Filename	Overview
src/BloomExe/Program.cs	Configures pseudo-localization before localization-manager initialization and safely falls back to English on channels where it is unavailable.
src/BloomExe/Workspace/WorkspaceView.cs	Adds a stable pseudo-locale label and places it last in the language menu while preserving existing selection behavior.
src/BloomExe/web/I18NApi.cs	Applies pseudo-localization to English fallback responses that bypass normal L10NSharp lookups, while excluding numeric IDs.
src/BloomExe/Book/TranslationGroupManager.cs	Prevents the testing-only pseudo-locale from generating persisted translated content in books.
src/BloomExe/web/controllers/CommonApi.cs	Excludes qps-ploc from the language chooser used to author persistent hint content.
src/BloomBrowserUI/react_components/TopBar/TopBar.tsx	Adds a stable language-independent data attribute to workspace tabs for automation.
.github/skills/bloom-automation/switchWorkspaceTab.mjs	Prefers the new stable workspace-tab selector while retaining legacy label-based fallbacks.
src/BloomTests/Workspace/PseudoLocalizationTests.cs	Covers pseudo-locale naming/completeness and non-development channel gating, though not the I18N fallback branches.
src/BloomExe/BloomExe.csproj	Upgrades L10NSharp to the beta version providing runtime pseudo-localization support.

_{Reviews (1): Last reviewed commit: "Merge remote-tracking branch 'origin/mas..." | Re-trigger Greptile}

[andrew-polk]

[Claude Opus 5 (1M context) during preflight] Consulted Devin on 2026-09-02 18:29 UTC up to commit c64f5ade54ef2a5c3c2a23bc14a8d658319b37d7.

Clean: no bugs, no Investigate flags, no informational items. Nothing to mirror.