The new oauth.copyCode/copyFailed keys existed only in en.ts, with
optional types and English literal fallbacks in OAuthLoginModal — so
non-English users got English strings on the device-code copy button.
Backfill translations in all 16 non-English locales, refresh the
updated oauth.description/notConnected copy (dashboard Login flow
mention) to match en.ts, make the two keys required in the
Translations interface, and drop the English fallbacks from the modal.
Verified with web tsc --noEmit (required keys enforce locale
completeness), vitest, and a web build.
ad8f103048