Enhance passkey registration handling with error checks and CORS support

Add validation for server response in the registration process, ensuring the presence of necessary options. Implement CORS headers for cross-device authentication and increase the timeout for registration to 5 minutes. Include debug logging for options structure to aid in troubleshooting.

pages/registrieren.vue

@@ -334,7 +334,19 @@ const handleRegisterWithPasskey = async () => {
       }
     })
 
+    if (!pre.success || !pre.options) {
+      throw new Error('Ungültige Antwort vom Server')
+    }
+
+    // Debug: Prüfe Options-Struktur
+    if (!pre.options.challenge) {
+      console.error('Options fehlen challenge:', pre.options)
+      throw new Error('Ungültige WebAuthn-Options vom Server')
+    }
+
     const mod = await import('@simplewebauthn/browser')
+    // startRegistration erwartet die Options direkt, nicht verschachtelt
+    // @simplewebauthn/browser v13+ erwartet die Options direkt
     const credential = await mod.startRegistration(pre.options)
 
     const response = await $fetch('/api/auth/register-passkey', {