Fix gallery issues: user uploads, error messages, and translations

- Fix user upload feature not showing in gallery
  - Add allow_user_uploads and upload_category_id to auth response
  - These fields are required for the gallery to show the upload button

- Improve gallery login error messages
  - Add specific translations for wrong password vs rate limiting
  - Map backend error messages to user-friendly translations
  - Added auth.wrongPassword and auth.tooManyAttempts keys

- Gallery pages already have full translation support
  - GalleryPage and GalleryView use i18n properly
  - All text is translated based on selected language

These fixes resolve:
1. User upload button not showing even when enabled
2. Generic error messages for wrong passwords
3. No feedback for rate limiting

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

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

backend/src/routes/auth.js

@@ -115,7 +115,9 @@ router.post('/gallery/verify', [
         event_date: event.event_date,
         welcome_message: event.welcome_message,
         color_theme: event.color_theme,
-        expires_at: event.expires_at
+        expires_at: event.expires_at,
+        allow_user_uploads: event.allow_user_uploads,
+        upload_category_id: event.upload_category_id
       }
     });
   } catch (error) {

frontend/src/i18n/locales/de.json

@@ -99,6 +99,8 @@
     "enterPassword": "Galerie-Passwort eingeben",
     "passwordPlaceholder": "Geben Sie das Galerie-Passwort ein",
     "invalidPassword": "Ungültiges Passwort",
+    "wrongPassword": "Falsches Passwort. Bitte überprüfen Sie Ihr Passwort und versuchen Sie es erneut.",
+    "tooManyAttempts": "Zu viele fehlgeschlagene Anmeldeversuche. Bitte versuchen Sie es später erneut.",
     "sessionExpired": "Sitzung abgelaufen",
     "pleaseEnterPassword": "Bitte geben Sie ein Passwort ein",
     "passwordHint": "Das Passwort wurde vom Veranstalter bereitgestellt. Kontaktieren Sie ihn, wenn Sie es nicht haben."

frontend/src/i18n/locales/en.json

@@ -99,6 +99,8 @@
     "enterPassword": "Enter Gallery Password",
     "passwordPlaceholder": "Enter the gallery password",
     "invalidPassword": "Invalid password",
+    "wrongPassword": "Incorrect password. Please check your password and try again.",
+    "tooManyAttempts": "Too many failed login attempts. Please try again later.",
     "sessionExpired": "Session expired",
     "pleaseEnterPassword": "Please enter a password",
     "passwordHint": "The password was provided by the event organizer. Contact them if you don't have it."

frontend/src/pages/GalleryPage.tsx

@@ -66,7 +66,16 @@ export const GalleryPage: React.FC = () => {
         success: true
       });
     } catch (error: any) {
-      setLoginError(error.response?.data?.error || t('auth.invalidPassword'));
+      const errorMessage = error.response?.data?.error || 'Invalid password';
+      
+      // Map backend error messages to user-friendly translations
+      if (errorMessage.toLowerCase().includes('invalid password')) {
+        setLoginError(t('auth.wrongPassword'));
+      } else if (error.response?.status === 429 || errorMessage.toLowerCase().includes('too many')) {
+        setLoginError(t('auth.tooManyAttempts'));
+      } else {
+        setLoginError(t('auth.invalidPassword'));
+      }
       
       // Track failed password entry
       analyticsService.trackGalleryEvent('password_entry', {