feat(i18n-ko): shared UI — packages/ui and core error copy

## Problem

Shared UI (`packages/ui`) and core error copy have no `ko`. In `ko`, shared components (conversation chrome, skills, scheduled tasks, shell controls) and connection errors still render in English or fall back incorrectly.

## Desired outcome

Add `ko` via `UiCatalog` for:

- `packages/ui/src/*copy.ts` (8 files): `astryx-copy.ts`, `conversation-copy.ts`, `daily-review-copy.ts`, `runtime-resume-copy.ts`, `scheduled-task-copy.ts`, `shared-ui-copy.ts`, `shell-controls-copy.ts`, `skills-copy.ts`
- `packages/core/src/connection-error-copy.ts` and related error catalogs
- Main-process fallbacks that are UI-facing: `client-settings-confirmation-copy.ts`, `runtime-host-*copy.ts`, `native-diagnostic-dialog.ts`, `notifications-policy.ts`, `permission-overlay-copy.ts`, `project-picker-copy.ts` (as covered in #3853 follow-up: explicit `ko` for non-catalog fallbacks)

## Alternatives or workarounds

Keep shared UI in English for `ko`.

## Acceptance criteria

- [ ] `ko` renders Korean for shared UI and error surfaces; `en` shows no Korean
- [ ] No Simplified Chinese leakage into `ko` (as fixed for `zh-TW` in #3853)
- [ ] Tests: `desktop-native-copy`, `health-center-copy`, `provider-connection-status` etc. updated for `ko`

Parent: #3974