feat(i18n-ko): desktop slice 1 — settings-preferences/onboarding/shell/permissions

[me2seeks]

Problem

Desktop Settings / Onboarding / Shell surfaces have no ko catalog. Korean users see English fallback for the most visible entry points (language selector, onboarding, shell chrome, permissions).

Desired outcome

Add ko entries via UiCatalog<T> for:

• settings-preferences-copy.ts (including language selector labels: Follow system / 한국어 / English / 中文)
• onboarding-copy.ts
• shell-copy.ts + shell-remaining-copy.ts
• permission-center-copy.ts

Follows domain-owned catalog pattern in #2672; content lives next to its UI, as in #3853.

Alternatives or workarounds

Leave these surfaces in English for ko.

Scope

Only the four domains above. No global catalog, no framework change. Other settings-* / conversation / artifact / browser covered in slice 2.

Acceptance criteria

• ko selected → the four domains render Korean, en shows no Korean
• auto + ko-KR system → ko (via parent feat(i18n): add Korean (ko) locale #3974 core change)
• npm run lint && npm run format:check && npm run build && npm run typecheck green
• Unit tests: settings-preferences-copy.test.ts etc. cover ko
• Screenshots: Settings at 1280 + 430 for en/ko (as in feat(i18n): add Traditional Chinese locale #3853 / fix(desktop): keep Agent Graph results label from shrinking #3970)

Parent: #3974