feat(i18n-ko): localize Desktop slice 2 catalogs

[bug-superman]

Summary

• Add Korean (ko) support to the Desktop slice-2 catalogs: conversation, artifact, browser, external-session import, MCP, Plan Mode, settings domains, and provider settings.
• Extend locale resolution for ko, ko-KR, and ko_KR, including ko-KR Intl formatting and Korean dynamic health/inspector/status copy.
• Add focused Korean catalog coverage for visible copy, English leakage, interpolation, dynamic counts, and locale selector entries.

Fixes #3976

Verification

• npm --workspace @maka/core run build ✅
• Workspace builds for storage, MCP, runtime, runtime-host, computer-use, eval, maka-agent ✅
• npm --workspace @maka/desktop run build:test ✅
• Core dist tests: 774 passing ✅
• Korean Desktop catalog tests: 3 passing ✅
• Targeted Desktop locale tests: 11 passing ✅
• npm run lint -- --error-on-warnings ✅
• npm run format:check ✅
• Renderer architecture check ✅

Notes

• Full UI typecheck/build remains blocked by pre-existing shared UI errors involving settledText, autoScroll, MarkdownProps, and trailingAction; no changed Korean catalog is implicated.
• Full Desktop dist tests have two unrelated Electron attestation failures (TUF/Sigstore ECDSA verification).
• UiLocale is shared by the repository, so a few unlisted catalogs also need an explicit ko slot to satisfy UiCatalog<T>; shared UI remains English fallback for feat(i18n-ko): shared UI — packages/ui and core error copy #3978, while slice-1/native additions should be split into their owning follow-up issues (feat(i18n-ko): desktop slice 1 — settings-preferences/onboarding/shell/permissions #3977/feat(i18n-ko): native surfaces and E2E fixtures #3980).
• Representative conversation/Plan Mode screenshots still need to be added by the screenshot workflow.