feat: notifications, audit logging, and admin improvements

- Add centralized notification service with webhook (Discord/Slack) and
  email (SMTP) support, triggered for trip invites, booking changes,
  collab messages, and trip reminders
- Webhook sends one message per event (group channel); email sends
  individually per trip member, excluding the actor
- Discord invite notifications now include the invited user's name
- Add LOG_LEVEL env var (info/debug) controlling console and file output
- INFO logs show user email, action, and IP for audit events; errors
  for HTTP requests
- DEBUG logs show every request with full body/query (passwords redacted),
  audit details, notification params, and webhook payloads
- Add persistent trek.log file logging with 10MB rotation (5 files)
  in /app/data/logs/
- Color-coded log levels in Docker console output
- Timestamps without timezone name (user sets TZ via Docker)
- Add Test Webhook and Save buttons to admin notification settings
- Move notification event toggles to admin panel
- Add daily trip reminder scheduler (9 AM, timezone-aware)
- Wire up booking create/update/delete and collab message notifications
- Add i18n keys for notification UI across all 13 languages

Made-with: Cursor

server/src/routes/notifications.ts

@@ -2,7 +2,7 @@ import express, { Request, Response } from 'express';
 import { db } from '../db/database';
 import { authenticate } from '../middleware/auth';
 import { AuthRequest } from '../types';
-import { testSmtp } from '../services/notifications';
+import { testSmtp, testWebhook } from '../services/notifications';
 
 const router = express.Router();
 
@@ -55,4 +55,13 @@ router.post('/test-smtp', authenticate, async (req: Request, res: Response) => {
   res.json(result);
 });
 
+// Admin: test webhook configuration
+router.post('/test-webhook', authenticate, async (req: Request, res: Response) => {
+  const authReq = req as AuthRequest;
+  if (authReq.user.role !== 'admin') return res.status(403).json({ error: 'Admin only' });
+
+  const result = await testWebhook();
+  res.json(result);
+});
+
 export default router;