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>
