fix: add language detection from app_settings and fix activity_logs schema

- Enhanced language detection priority in email processor:
  1. Event-specific language
  2. App settings general_default_language (NEW)
  3. Email config default_language
  4. Domain-based detection
- Fixed activity_logs insertion error by using logActivity function
- Fixed 500 error on resend email endpoint
- Emails now respect language selected in settings page

backend/scripts/check-german-templates.js

@@ -0,0 +1,53 @@
+const { db } = require('../src/database/db');
+
+async function checkGermanTemplates() {
+  try {
+    console.log('=== German Email Template Content Check ===\n');
+    
+    const templates = await db('email_templates').select('*');
+    
+    for (const template of templates) {
+      console.log(`\nTemplate: ${template.template_key}`);
+      console.log('=====================================');
+      
+      // Check German subject
+      console.log('\nGERMAN SUBJECT:');
+      console.log(template.subject_de || 'MISSING');
+      
+      // Check if German HTML body has English content
+      console.log('\nGERMAN HTML BODY:');
+      const germanHtml = template.body_html_de || '';
+      
+      // Check for English phrases in German template
+      const englishPhrases = [
+        'Dear', 'Gallery', 'has been', 'Your photo', 'successfully',
+        'Details:', 'Link:', 'Password:', 'Expires:', 'Event Date:',
+        'Thank you', 'Best regards', 'View Gallery', 'days'
+      ];
+      
+      const foundEnglish = englishPhrases.filter(phrase => 
+        germanHtml.toLowerCase().includes(phrase.toLowerCase())
+      );
+      
+      if (foundEnglish.length > 0) {
+        console.log('⚠️  Found English phrases in German template:', foundEnglish.join(', '));
+      }
+      
+      // Show first 500 chars of German HTML
+      console.log(germanHtml.substring(0, 500) + '...\n');
+      
+      // Check German text body
+      console.log('GERMAN TEXT BODY:');
+      const germanText = template.body_text_de || '';
+      console.log(germanText.substring(0, 300) + '...\n');
+    }
+    
+    await db.destroy();
+  } catch (error) {
+    console.error('Error:', error);
+    await db.destroy();
+    process.exit(1);
+  }
+}
+
+checkGermanTemplates();