feat(V2-1c): packages/ui 추출 — DS 컴포넌트 + theme + theme-vars 분리

packages/ui (@d3ro/ui) 신규:
- src/theme.ts (d3roPalette/d3roTypo/d3roShadow/d3roRadius SSOT)
- src/theme-vars.ts (팝업/main 프로세스용 CSS 변수 맵)
- src/components/ds/ (CrtDisplay, InstrumentPanel, Led, MetalCard,
  MetalDial, PhosphorText, PhysicalButton, ScreenPanel, ButtonGroup)
- src/index.ts barrel
- subpath exports: ./theme, ./theme-vars, ./components/ds
- React/MUI/Emotion은 peerDependencies로 선언
- @d3ro/core만 직접 의존성

apps/desktop/src/shared/ 디렉토리 완전 제거:
- theme-vars가 마지막 남은 파일이었음
- tsconfig include에서 src/shared/**/* 제거

일괄 치환 (renderer 전역):
- ../theme, ../../theme, ./theme → @d3ro/ui/theme
- ../components/ds, ../../components/ds, ./ds, ../ds → @d3ro/ui/components/ds
- ../ds/<Component>, ../../ds/<Component> → @d3ro/ui/components/ds
  (세부 파일 import는 barrel로 통합)
- @shared/theme-vars → @d3ro/ui/theme-vars (WindowManager)

apps/desktop 설정:
- package.json: @d3ro/ui: '*' dep 추가
- tsconfig.node/web.json: @shared/* paths 완전 제거, @d3ro/ui,
  @d3ro/ui/* paths 추가
- electron.vite.config.ts: @shared alias 제거, @d3ro/ui alias 추가,
  externalize exclude에 @d3ro/ui 추가
- vitest.config.ts: alias 교체

DS 컴포넌트 내부의 '../../theme' 상대 경로는 packages/ui 구조에서
동일하게 해결되어 그대로 유효.

검증: typecheck + build + dev 런타임 모두 통과.

apps/desktop/src/renderer/pages/KnowledgeBasePage.tsx

@@ -10,9 +10,9 @@ import RefreshIcon from '@mui/icons-material/Refresh'
 import SearchIcon from '@mui/icons-material/Search'
 import SendIcon from '@mui/icons-material/Send'
 import DescriptionIcon from '@mui/icons-material/Description'
-import { MetalCard, PhosphorText, Led, PhysicalButton, ScreenPanel } from '../components/ds'
+import { MetalCard, PhosphorText, Led, PhysicalButton, ScreenPanel } from '@d3ro/ui/components/ds'
 import { PageHeader, EmptyStateCard } from '../components/shared'
-import { d3roPalette, d3roFontMono, d3roTypo } from '../theme'
+import { d3roPalette, d3roFontMono, d3roTypo } from '@d3ro/ui/theme'
 import { useI18n } from '../i18n'
 import type { RAGDocument, RAGQueryResult, RAGIndexProgress } from '@d3ro/core/types'