refactor(main): IPC 채널 SSOT 일원화 + AppConfig 타입 강화 (WS2)

- ipc-channels.ts SSOT에 9개 그룹/키 추가: INSTRUCTION, SYSTEM_AUDIO,
  POPUP_RESULT/HISTORY/COMMAND/CAPTION, VOICE_PARTIAL, CLIPBOARD, APP,
  VOICE_CONVERSATION.FINISH_LISTENING
- WindowManager/handlers/bootstrap 하드코딩 채널 -> IPC_CHANNELS 교체.
  불일치 4건(result:* vs window:tip*)은 preload 재검증 후 SSOT로 통일.
  notifyRenderer channel: string -> IPCChannel 타입 좁힘.
- AppConfig에 7개 누락 키 추가(customInstructions, llmChains,
  voiceCommandRules, voiceCommandsEnabled, activeInstructionId,
  activeChainId, captionAudioSource) -> as never 16건 제거.
- ChainService/CustomInstructionService/WindowManager dynamic require -> static import.
- services/index.ts 데드 레지스트리 제거 (import 0건).
SKIP: ipcSuccess/ipcError 헬퍼 통일, catch 패턴(별도)
정책: docs/REFACTOR_POLICY.md DP2, DP9

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

@@ -3,26 +3,11 @@
 // electron-store에 저장, 프리셋 5개 기본 제공.
 
 import { getLogger } from './LoggerService'
-import { configGet } from './ConfigService'
+import { configGet, configSet } from './ConfigService'
+import type { CustomInstruction } from '@d3ro/core/types'
 
 const logger = getLogger('CustomInstructionService')
 
-// ============================================================
-// 타입
-// ============================================================
-
-export interface CustomInstruction {
-  id: string
-  name: string
-  description: string
-  prompt: string
-  icon: string
-  isBuiltin: boolean
-  order: number
-  createdAt: number
-  updatedAt: number
-}
-
 type CreateInput = Omit<CustomInstruction, 'id' | 'isBuiltin' | 'order' | 'createdAt' | 'updatedAt'>
 
 // ============================================================
@@ -91,7 +76,7 @@ let initialized = false
 function loadInstructions(): CustomInstruction[] {
   // electron-store에서 로드 시도
   try {
-    const stored = configGet('customInstructions' as never) as CustomInstruction[] | undefined
+    const stored = configGet('customInstructions') as CustomInstruction[] | undefined
     if (Array.isArray(stored) && stored.length > 0) {
       return stored
     }
@@ -110,8 +95,7 @@ function loadInstructions(): CustomInstruction[] {
 
 function saveInstructions(): void {
   try {
-    const { configSet } = require('./ConfigService')
-    configSet('customInstructions' as never, instructions as never)
+    configSet('customInstructions', instructions)
   } catch (error) {
     logger.warn(`Failed to save instructions: ${error instanceof Error ? error.message : String(error)}`)
   }