Exercise-name packs for it/de/es/fr plus two per-language English-name toggles

[giulioleuci]

Closes #253

Summary

Adds complete exercise-name packs for Italian (it), German (de), Spanish (es) and French (fr) — each translating the full 1,324-exercise built-in catalogue — plus two independent per-language toggles in Settings:

• "English exercise names" — the "(English)" parenthetical that follows translated names, now a per-language setting (previously always shown for the newly added languages).
• "English names only" — replaces the translated name with the original English one; while it is on, the parenthetical toggle is disabled for that language since the English name is already the displayed one.

Languages that already had translated packs (pt-BR, hu) are unaffected; each language remembers its own choice; de-CH keeps inheriting the German pack through the existing derivePack transform (ß→ss), so no extra pack to maintain.

What changes

1. Exercise-name packs — every pack is generated by a build script from an authored JSON source (scripts/exercise-name-sources/*.json → scripts/build-*-exercise-names.mjs → frontend/src/exercise-names/*.js). The scripts fail hard on unknown ids, empty values or an incomplete count. Each pack ships a unit test asserting full catalogue coverage plus per-language translation rules (barbell→Langhantel/barra/barre/... dumbbell→Kurzhantel/mancuerna/haltère/... etc.).

2. Per-language "(English name)" toggle (#253, point 2) — the English parenthetical that follows translated exercise names is now a per-language user setting:

   • persisted per-language map (DEF.enParens = {}) in the store, defaulting to shown so existing profiles keep today's rendering;
   • Settings shows a single adaptive switch bound to the active language, remembered separately for each language;
   • the toggle row is hidden for languages without an exercise pack, so the option never appears for languages that cannot use it;
   • the app re-applies the exercise-name rendering when the setting changes.

3. New "English names only" per-language toggle — drops the translation entirely and shows the original English name. Since the parenthetical is redundant in this mode, the "English exercise names" switch is disabled (greyed out) while it is active. The two labels are translated in all 14 packs.

4. i18n — the new Settings labels are translated in all 14 locale packs (including a Brazilian-Portuguese override), with a locale-coverage.test.js asserting the keys exist and are non-blank in every shipped pack.

Notes on translations

The exercise names in the it/de/es/fr packs were translated from English by an LLM (OpenCode Zen), then reviewed against the exercise catalogue. Please give them a native-speaker pass before relying on them in production.

Tests

Full frontend suite passes: 131 files / 1,611 tests (same Node 22 runtime as the CI gate). No new dependencies.

Issue

Fixes #253 — exercise-name packs for it/de/es/fr plus the per-language "English name in parentheses" toggle and a companion "English names only" toggle.

[giulioleuci]

Implement #253

[DuarteSantos8]

Thanks @giulioleuci. From this PR the Italian and French name packs and the two per-language toggles (English in parentheses / English only) are in v1.3.9.

I didn't take your German and Spanish packs: German comes from #290 (@mkoester, partly native-reviewed) and Spanish from #245 (@AlexRomero12, opened first). Your toggles work with those packs and with Russian (#266) as well. I also removed the stray ISSUE_ON_GITHUB.md, and an English-only name is title-cased again.

If you know an Italian or French speaker who could read through the names, a review PR would be very welcome.

Released in v1.3.9: https://github.com/DuarteSantos8/openGym/releases/tag/v1.3.9