Fix backend 500 errors for event creation and system version

- Fix system version endpoint to read package.json using fs instead of require
  - Prevents MODULE_NOT_FOUND error in Docker container
  - Uses path.join to find package.json reliably

- Fix event creation email queue error
  - Change email_type from 'creation' to 'gallery_created' to match template key
  - Update email_data to include all required template variables
  - Added missing created_at and updated_at columns to email_queue table

- Fix file watcher duplicate photo insertion
  - Add check to prevent re-inserting existing photos on backend restart

These fixes resolve:
1. 500 error when accessing /api/admin/system/version
2. 500 error when creating new events
3. Email queue processing errors
4. Photo duplication issue

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

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

backend/src/routes/adminEvents.js

@@ -99,12 +99,14 @@ router.post('/', adminAuth, [
     await db('email_queue').insert({
       event_id: eventId,
       recipient_email: host_email,
-      email_type: 'creation',
+      email_type: 'gallery_created',
       email_data: JSON.stringify({
+        host_name: host_email.split('@')[0], // Extract name from email
         event_name,
-        share_link: shareLink,
-        password,
-        expires_at: expires_at.toISOString()
+        event_date: new Date(event_date).toLocaleDateString(),
+        gallery_link: shareLink,
+        gallery_password: password,
+        expiry_date: expires_at.toLocaleDateString()
       })
       // scheduled_at will use default value
     });