feat(V2-1b): packages/core 추출 — 공유 타입/에러/채널/유틸 분리

packages/core (@d3ro/core) 신규 생성:
- types.ts, errors.ts, ipc-channels.ts, constants.ts (shared에서 이동)
- utils/meeting-markdown.ts, utils/markdown-to-docx.ts (main/utils에서 이동)
- subpath exports 정의 (./types, ./errors, ./ipc-channels, ./constants,
  ./utils/meeting-markdown, ./utils/markdown-to-docx)
- src/index.ts barrel export 추가
- docx를 core 자체 dependency로 선언

apps/desktop 연결:
- package.json에 @d3ro/core: '*' dep 추가
- tsconfig.node/web.json paths에 @d3ro/core/* 추가
- electron.vite.config.ts 3개 섹션 alias 추가 (main/preload/renderer)
- externalizeDepsPlugin exclude에 @d3ro/core (workspace 소스 번들 대상)
- vitest.config.ts alias 추가

일괄 치환 (79 파일, 167건):
- @shared/{types,errors,ipc-channels,constants} → @d3ro/core/*
- static/dynamic import + type expression import 모두 포함
- MeetingModeService.ts의 ../utils/* 상대 경로 → @d3ro/core/utils/*
- @shared/theme-vars는 V2-1c 범위로 남김 (WindowManager만 사용)

M1 수정 포함:
- electron.vite.config.ts의 resolve('src/shared') → resolve(__dirname, ...)
  CWD 독립적으로 동작하도록 견고화

검증:
- typecheck 통과
- build 통과 (main+preload+renderer)
- dev 런타임 → DB/핫키/Ollama 모두 정상, 기존 데이터 연속성 유지

apps/desktop/src/main/services/MeetingModeService.ts

@@ -12,8 +12,8 @@ import { configGet, configSet } from './ConfigService'
 import { getMainWindow } from '../windows/WindowManager'
 import { getDatabase } from '../db'
 import { meetingSessions, meetingMemos, meetingDocuments } from '../db/schema'
-import { IPC_CHANNELS } from '@shared/ipc-channels'
-import { D3ROError, ErrorCode } from '@shared/errors'
+import { IPC_CHANNELS } from '@d3ro/core/ipc-channels'
+import { D3ROError, ErrorCode } from '@d3ro/core/errors'
 import {
   parseMinutes,
   buildExportMarkdown,
@@ -21,8 +21,8 @@ import {
   formatTime,
   formatDateFile,
   formatDateRange,
-} from '../utils/meeting-markdown'
-import { markdownToDocx } from '../utils/markdown-to-docx'
+} from '@d3ro/core/utils/meeting-markdown'
+import { markdownToDocx } from '@d3ro/core/utils/markdown-to-docx'
 import type {
   MeetingModeState,
   MeetingMemo,
@@ -39,7 +39,7 @@ import type {
   MeetingExportFormat,
   MeetingDocGeneratingProgress,
   CaptionSegment,
-} from '@shared/types'
+} from '@d3ro/core/types'
 
 const logger = getLogger('MeetingModeService')
 
@@ -145,7 +145,7 @@ class MeetingModeService extends EventEmitter {
 
     // 회의 모드는 마이크 캡처 강제 — ConfigService 값도 임시 변경
     // (CaptionService.start()가 ConfigService에서 다시 읽기 때문)
-    type AppConfigKey = keyof import('@shared/types').AppConfig
+    type AppConfigKey = keyof import('@d3ro/core/types').AppConfig
     const prevAudioSource = configGet('captionAudioSource' as AppConfigKey) as unknown as string
     configSet('captionAudioSource' as AppConfigKey, 'mic' as never)