feat(logging): Wave 2 - integrate logging throughout application

This commit integrates the logging infrastructure across the entire application:

IPC Layer:
- Add logger-handler.ts with centralized IPC logging channels
- Integrate audit logging into auth, cleaner, extractor handlers
- Add structured logging for IPC operations and data flow

Service Layer:
- Add logger integration to ERP services (extractor, cleaner)
- Integrate logging into excel-parser and user DAO
- Add operation tracking and error logging

Renderer Layer:
- Add useLogger hook for component-level logging
- Update App.tsx with session and user activity logging
- Enable frontend audit trail for critical actions

Testing:
- Add comprehensive IPC logging integration tests
- Enhance unit test coverage for logger and audit-logger
- Add end-to-end logging flow validation

Types:
- Update preload type definitions for logging APIs

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/main/ipc/settings-handler.ts

@@ -5,6 +5,7 @@ import { UserErpConfigService } from '../services/user/user-erp-config-service'
 import { MySqlService } from '../services/database/mysql'
 import { SqlServerService } from '../services/database/sql-server'
 import { createLogger } from '../services/logger'
+import { logAudit } from '../services/logger/audit-logger'
 import type { UserType, ConnectionTestResult, SaveSettingsResult } from '../types/settings.types'
 import { IPC_CHANNELS } from '../../shared/ipc-channels'
 import { ValidationError } from '../types/errors'
@@ -60,6 +61,16 @@ export function registerSettingsHandlers(): void {
             username: settings.erp.username || '',
             password: settings.erp.password || ''
           })
+
+          // Audit log: SETTINGS_CHANGE (non-blocking)
+          const os = await import('os')
+          logAudit('SETTINGS_CHANGE', String(currentUser.id), {
+            username: currentUser.username,
+            computerName: os.hostname(),
+            resource: 'ERP_CONFIG',
+            status: 'success',
+            metadata: { changeType: 'erp_credentials', usernameChanged: !!settings.erp.username }
+          }).catch((err) => log.warn('Failed to write audit log', { err }))
         }
 
         return { success: true }
@@ -164,4 +175,3 @@ export function registerSettingsHandlers(): void {
     }
   )
 }
-