events: record login event on POST /auth/login success

src/auth.js

@@ -17,6 +17,7 @@ import { Router } from 'express';
 import { q } from './db.js';
 import { issueSession, clearSession } from './sessions.js';
 import { rateLimit } from './middleware.js';
+import { recordEvent } from './events.js';
 
 const router = Router();
 
@@ -51,7 +52,8 @@ router.post(
       return res.status(403).json({ error: 'not_invited' });
     }
 
-    issueSession(req, res, email);
+    const sessionId = issueSession(req, res, email);
+    recordEvent(req, { type: 'login', email, sessionId });
     return res.status(200).json({
       ok: true,
       firstName: invited.first_name || null,