Fix mobile responsiveness and implement enhanced theme system

- Fixed mobile gallery login box sizing and layout
- Fixed header button layout for mobile screens
- Fixed duplicate logo issue on logout
- Fixed '0' rendering when upload button is hidden
- Fixed horizontal scrolling on small screens

- Implemented comprehensive theme system with gallery layouts
- Added 6 different gallery layouts: Grid, Masonry, Carousel, Timeline, Hero, Mosaic
- Created enhanced theme customizer with layout selection
- Added theme presets for different event types
- Updated event creation with theme preview and customization
- Fixed all TypeScript compilation errors

- Added missing translation keys for create event page
- Added translations for theme customization features

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

Co-Authored-By: Claude <[email protected]>

frontend/src/i18n/locales/de.json

@@ -29,7 +29,9 @@
     "preview": "Vorschau",
     "processing": "Wird verarbeitet...",
     "upload": "Hochladen",
-    "days": "Tage"
+    "days": "Tage",
+    "customize": "Anpassen",
+    "hide": "Ausblenden"
   },
   "upload": {
     "photoCategory": "Fotokategorie",
@@ -163,6 +165,7 @@
   },
   "events": {
     "title": "Veranstaltungen",
+    "create": "Veranstaltung erstellen",
     "createEvent": "Veranstaltung erstellen",
     "eventDetails": "Veranstaltungsdetails",
     "eventName": "Veranstaltungsname",
@@ -221,16 +224,21 @@
     "adminEmailHelp": "Erhält Systembenachrichtigungen und Archivbestätigungen",
     "securityAccess": "Sicherheit & Zugriff",
     "galleryPassword": "Galerie-Passwort",
+    "passwordPlaceholder": "Sicheres Passwort eingeben",
     "confirmPassword": "Passwort bestätigen",
     "showPasswords": "Passwörter anzeigen",
     "gallerySettings": "Galerie-Einstellungen",
     "colorTheme": "Farbthema",
+    "galleryExpiration": "Galerie-Ablauf",
     "galleryExpiresIn": "Galerie läuft ab in",
+    "daysAfterEvent": "Tage nach der Veranstaltung",
+    "themeAndStyle": "Design & Stil",
     "galleryWillExpireOn": "Galerie läuft ab am {{date}}",
     "expirationWarning": "Gäste erhalten 7 Tage vor Ablauf eine Warn-E-Mail.",
     "userUploads": "Benutzer-Upload-Einstellungen",
     "allowUserUploads": "Gästen erlauben, Fotos hochzuladen",
     "allowUserUploadsHelp": "Ermöglichen Sie Gästen, ihre eigenen Fotos in diese Galerie hochzuladen",
+    "allowUserUploadsDescription": "Ermöglichen Sie Gästen, ihre eigenen Fotos in diese Galerie hochzuladen",
     "uploadCategory": "Upload-Kategorie",
     "selectCategory": "Wählen Sie eine Kategorie für Benutzer-Uploads",
     "uploadCategoryHelp": "Alle von Benutzern hochgeladenen Fotos werden dieser Kategorie hinzugefügt",
@@ -253,6 +261,7 @@
     "hostEmailPlaceholder": "[email protected]",
     "adminEmailPlaceholder": "[email protected]",
     "securityAndAccess": "Sicherheit & Zugriff",
+    "accessAndSecurity": "Zugriff & Sicherheit",
     "enterPassword": "Passwort eingeben",
     "confirmPasswordPlaceholder": "Passwort bestätigen",
     "galleryExpiresOn": "Galerie läuft ab am {{date}}",
@@ -512,7 +521,9 @@
     "oopsSomethingWentWrong": "Ups! Etwas ist schiefgelaufen",
     "unexpectedError": "Es ist ein unerwarteter Fehler aufgetreten. Keine Sorge, Ihre Daten sind sicher.",
     "goToHomepage": "Zur Startseite",
-    "errorDetails": "Fehlerdetails"
+    "errorDetails": "Fehlerdetails",
+    "failedToCreateEvent": "Fehler beim Erstellen der Veranstaltung",
+    "eventCreationFailed": "Fehler beim Erstellen der Veranstaltung"
   },
   "legal": {
     "impressum": "Impressum",

frontend/src/i18n/locales/en.json

@@ -29,7 +29,9 @@
     "preview": "Preview",
     "processing": "Processing...",
     "upload": "Upload",
-    "days": "days"
+    "days": "days",
+    "customize": "Customize",
+    "hide": "Hide"
   },
   "upload": {
     "photoCategory": "Photo Category",
@@ -575,6 +577,7 @@
     "requiredFields": "Please fill in all required fields",
     "enterTestEmail": "Please enter a test email address",
     "failedToCreateEvent": "Failed to create event",
+    "eventCreationFailed": "Failed to create event",
     "networkError": "Network error. Please check your connection and try again.",
     "sessionExpired": "Session expired. Please login again."
   },