refactor(main): ipcSuccess/ipcError 헬퍼 통일 + catch(error) 패턴 (WS-PATTERN)

- cloud-sync-handlers 수동 ok/fail -> ipcSuccess/ipcError 헬퍼 (6 핸들러)
- catch {} -> catch(error) 에러 메시지 보강 32건 (11 ipc handler 파일)
KEEP: template-handlers(주석 명시 에러 무시), license-handlers(이미 헬퍼 사용),
       audio-handlers stop().catch(() => {})(의도적 무시)
정책: docs/REFACTOR_POLICY.md DP2

apps/desktop/src/main/ipc/config-handlers.ts

@@ -28,8 +28,9 @@ export function registerConfigHandlers(): void {
   ipcMain.handle(IPC_CHANNELS.CONFIG.GET, async (_event, params: ConfigGetParams) => {
     try {
       return ipcSuccess(configGet(params.key))
-    } catch {
-      return ipcError(ErrorCode.ConfigReadFailed, `Failed to read config key: ${params.key}`)
+    } catch (error) {
+      const message = error instanceof Error ? error.message : String(error)
+      return ipcError(ErrorCode.ConfigReadFailed, `Failed to read config key ${params.key}: ${message}`)
     }
   })
 
@@ -39,8 +40,9 @@ export function registerConfigHandlers(): void {
       configSet(params.key, params.value as AppConfig[typeof params.key])
       broadcastConfigChanged(params.key, params.value, prev)
       return ipcSuccess(undefined)
-    } catch {
-      return ipcError(ErrorCode.ConfigWriteFailed, `Failed to write config key: ${params.key}`)
+    } catch (error) {
+      const message = error instanceof Error ? error.message : String(error)
+      return ipcError(ErrorCode.ConfigWriteFailed, `Failed to write config key ${params.key}: ${message}`)
     }
   })
 
@@ -52,8 +54,9 @@ export function registerConfigHandlers(): void {
     try {
       configReset(params.key)
       return ipcSuccess(undefined)
-    } catch {
-      return ipcError(ErrorCode.ConfigResetFailed, 'Failed to reset config')
+    } catch (error) {
+      const message = error instanceof Error ? error.message : String(error)
+      return ipcError(ErrorCode.ConfigResetFailed, `Failed to reset config: ${message}`)
     }
   })