Fix: Slot reservation only after successful email validation

- Move email validation before slot reservation in backend
- Remove duplicate frontend email validation
- Slots are no longer blocked by failed booking attempts
- Clean up unused email error UI components
- Ensure slots remain available if email validation fails

src/server/lib/email-validator.ts

@@ -3,15 +3,17 @@
 // Privacy-focused, no data storage, completely free
 
 type EmailValidationResult = {
-  valid: boolean;
   email: string;
-  domain?: string;
-  disposable?: boolean;
-  role?: boolean;
-  typo?: boolean;
-  suggestion?: string;
-  mx?: boolean;
-  error?: string;
+  validations: {
+    syntax: boolean;
+    domain_exists: boolean;
+    mx_records: boolean;
+    mailbox_exists: boolean;
+    is_disposable: boolean;
+    is_role_based: boolean;
+  };
+  score: number;
+  status: string;
 };
 
 /**
@@ -25,7 +27,7 @@ export async function validateEmail(email: string): Promise<{
 }> {
   try {
     // Call Rapid Email Validator API
-    const response = await fetch(`https://rapid-email-verifier.fly.dev/verify/${encodeURIComponent(email)}`, {
+    const response = await fetch(`https://rapid-email-verifier.fly.dev/api/validate?email=${encodeURIComponent(email)}`, {
       method: 'GET',
       headers: {
         'Accept': 'application/json',
@@ -33,15 +35,18 @@ export async function validateEmail(email: string): Promise<{
     });
 
     if (!response.ok) {
-      console.warn(`Email validation API error: ${response.status}`);
-      // If API is down, allow the email (fallback to Zod validation only)
-      return { valid: true };
+      console.error(`Email validation API error: ${response.status}`);
+      // If API is down, reject the email with error message
+      return { 
+        valid: false, 
+        reason: 'E-Mail-Validierung ist derzeit nicht verfügbar. Bitte überprüfe deine E-Mail-Adresse und versuche es erneut.' 
+      };
     }
 
     const data: EmailValidationResult = await response.json();
 
     // Check if email is disposable/temporary
-    if (data.disposable) {
+    if (data.validations.is_disposable) {
       return {
         valid: false,
         reason: 'Temporäre oder Wegwerf-E-Mail-Adressen sind nicht erlaubt. Bitte verwende eine echte E-Mail-Adresse.',
@@ -49,20 +54,26 @@ export async function validateEmail(email: string): Promise<{
     }
 
     // Check if MX records exist (deliverable)
-    if (data.mx === false) {
+    if (!data.validations.mx_records) {
       return {
         valid: false,
         reason: 'Diese E-Mail-Adresse kann keine E-Mails empfangen. Bitte überprüfe deine E-Mail-Adresse.',
       };
     }
 
-    // Check if email is generally valid
-    if (!data.valid) {
-      const suggestion = data.suggestion ? ` Meintest du vielleicht: ${data.suggestion}?` : '';
+    // Check if domain exists
+    if (!data.validations.domain_exists) {
       return {
         valid: false,
-        reason: `Ungültige E-Mail-Adresse.${suggestion}`,
-        suggestion: data.suggestion,
+        reason: 'Die E-Mail-Domain existiert nicht. Bitte überprüfe deine E-Mail-Adresse.',
+      };
+    }
+
+    // Check if email syntax is valid
+    if (!data.validations.syntax) {
+      return {
+        valid: false,
+        reason: 'Ungültige E-Mail-Adresse. Bitte überprüfe die Schreibweise.',
       };
     }
 
@@ -71,9 +82,11 @@ export async function validateEmail(email: string): Promise<{
 
   } catch (error) {
     console.error('Email validation error:', error);
-    // If validation fails, allow the email (fallback to Zod validation only)
-    // This ensures the booking system continues to work even if the API is down
-    return { valid: true };
+    // If validation fails, reject the email with error message
+    return { 
+      valid: false, 
+      reason: 'E-Mail-Validierung ist derzeit nicht verfügbar. Bitte überprüfe deine E-Mail-Adresse und versuche es erneut.' 
+    };
   }
 }