Overhaul translation tooling and freeze bundled language assets

[Marc-André Moreau (mamoreau-devolutions)]

• I have read the contributing guidelines, and I agree with the Code of Conduct.
• Have you checked that there aren't other open pull requests for the same changes?
• Have you tested that the committed code can be executed without errors?
• This PR is not composed of garbage changes used to farm GitHub activity to enter potential Crypto AirDrops.
  Any user suspected of farming GitHub activity with crypto purposes will get banned. Submitting broken code wastes the contributors' time, who have to spend their free time reviewing, fixing, and testing code that does not even compile breaks other features, or does not introduce any useful changes. I appreciate your understanding.

---

This PR consolidates the translation tooling overhaul around bundled language assets.

• adds translation review, diff, source-sync, boundary-alignment, and locale reorder tooling
• introduces the English legacy boundary workflow and reorders locale files around that layout
• renames the translation status skill and makes status computation boundary-aware
• removes runtime reliance on downloaded translations and keeps language handling bundled-only
• updates related tests and experimental settings strings

Validation performed:

• pwsh ./scripts/translation/Verify-Translations.ps1
• pwsh ./.agents/skills/translation-source-sync/scripts/set-translation-boundary-order.ps1 -CheckOnly
• pwsh ./.agents/skills/translation-status/scripts/get-translation-status.ps1 -OutputFormat Json

---