refactor(logger): optimize logging architecture with 6 improvements

1. Extract shared module: consolidate getLogDir() and isProduction()
   into shared.ts, eliminate duplication across logger modules
2. Make retention config effective: delay file transport creation
   until config is loaded, apply appRetention/auditRetention from config.yaml
3. Add before-quit log flush: close logger and audit logger on
   app exit to prevent log loss
4. Unify logError entry point: remove duplicate logError from index.ts,
   re-export from error-utils.ts with richer error context
5. Renderer log level filtering: add client-side level check in preload
   to skip IPC for filtered-out messages
6. Child logger cache + audit cleanup: cache child loggers in IPC
   handler for performance, remove redundant timestamp format in audit logger

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/main/services/erp/extractor.ts

@@ -123,9 +123,7 @@ export class ExtractorService {
    * @param filePaths - Array of downloaded Excel file paths
    * @returns Merged file path, total record count, and optional error message
    */
-  private async mergeFiles(
-    filePaths: string[]
-  ): Promise<{
+  private async mergeFiles(filePaths: string[]): Promise<{
     mergedFile: string | null
     recordCount: number
     error?: string
@@ -197,7 +195,12 @@ export class ExtractorService {
       const errorStack = error instanceof Error ? error.stack : ''
       log.error('Failed to save merged file', { error: errorMsg, stack: errorStack })
       // Return parsed record count and error info even if save fails
-      return { mergedFile: null, recordCount, orderRecordCounts, error: `保存合并文件失败：${errorMsg}` }
+      return {
+        mergedFile: null,
+        recordCount,
+        orderRecordCounts,
+        error: `保存合并文件失败：${errorMsg}`
+      }
     }
   }