fix: prevent double date formatting in email templates

- Remove pre-formatting of dates before passing to email processor
- Let email processor handle all date formatting based on recipient language
- Fix Invalid Date errors by passing raw date values instead of formatted strings
- Remove unused formatDate imports and variables

🤖 Generated with [Claude Code](https://claude.ai/code)

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

backend/src/routes/adminEvents.js

@@ -10,7 +10,7 @@ const path = require('path');
 const { archiveEvent } = require('../services/archiveService');
 const { queueEmail } = require('../services/emailProcessor');
 const { escapeLikePattern } = require('../utils/sqlSecurity');
-const { formatDate } = require('../utils/dateFormatter');
+// formatDate import removed - dates are formatted by email processor
 const { validatePasswordInContext, getBcryptRounds } = require('../utils/passwordValidation');
 const { formatBoolean } = require('../utils/dbCompat');
 
@@ -135,8 +135,7 @@ router.post('/', adminAuth, [
     );
     
     // Queue creation email
-    // Determine language based on email domain
-    const emailLang = host_email.endsWith('.de') ? 'de' : 'en';
+    // Language detection is handled by email processor
     
     await db('email_queue').insert({
       event_id: eventId,
@@ -145,10 +144,10 @@ router.post('/', adminAuth, [
       email_data: JSON.stringify({
         host_name: host_name,
         event_name,
-        event_date: await formatDate(event_date, emailLang),
+        event_date: event_date,  // Pass raw date - will be formatted by email processor
         gallery_link: shareLink,
         gallery_password: password,
-        expiry_date: await formatDate(expires_at, emailLang),
+        expiry_date: expires_at.toISOString(),  // Pass ISO string - will be formatted by email processor
         welcome_message: welcome_message || ''
       }),
       status: 'pending',
@@ -553,10 +552,10 @@ router.post('/:id/reset-password', adminAuth, async (req, res) => {
       await queueEmail(id, event.host_email, 'gallery_created', {
         host_name: event.host_email.split('@')[0],
         event_name: event.event_name,
-        event_date: new Date(event.event_date).toLocaleDateString(),
+        event_date: event.event_date,  // Pass raw date - will be formatted by email processor
         gallery_link: event.share_link,
         gallery_password: newPassword,
-        expiry_date: new Date(event.expires_at).toLocaleDateString()
+        expiry_date: event.expires_at  // Pass raw date - will be formatted by email processor
       });
     }
 
@@ -603,18 +602,16 @@ router.post('/:id/resend-email', adminAuth, async (req, res) => {
       galleryPassword = '{{password_security_message}}';
     }
     
-    // Format dates in a neutral format - the email processor will localize them
-    const eventDate = new Date(event.event_date);
-    const expiryDate = new Date(event.expires_at);
+    // Dates will be formatted by the email processor based on recipient language
     
     // Queue the email
     await queueEmail(id, event.host_email, 'gallery_created', {
       host_name: event.host_name || event.host_email.split('@')[0],
       event_name: event.event_name,
-      event_date: eventDate.toISOString().split('T')[0], // YYYY-MM-DD format
+      event_date: event.event_date,  // Pass raw date - will be formatted by email processor
       gallery_link: event.share_link,
       gallery_password: galleryPassword,
-      expiry_date: expiryDate.toISOString().split('T')[0], // YYYY-MM-DD format
+      expiry_date: event.expires_at,  // Pass raw date - will be formatted by email processor
       welcome_message: event.welcome_message || '',
       eventId: id,
       isResend: true // Flag to indicate this is a resend