Fix Supabase linter warnings and backend validation

src/lib/emailValidation.ts

@@ -0,0 +1,35 @@
+import { supabase } from '@/integrations/supabase/client';
+
+interface EmailValidationResult {
+  valid: boolean;
+  reason?: string;
+  suggestions?: string[];
+}
+
+/**
+ * Validates an email address against disposable email domains
+ * Uses the validate-email edge function to check the backend blocklist
+ */
+export async function validateEmailNotDisposable(email: string): Promise<EmailValidationResult> {
+  try {
+    const { data, error } = await supabase.functions.invoke('validate-email', {
+      body: { email }
+    });
+
+    if (error) {
+      console.error('Email validation error:', error);
+      return {
+        valid: false,
+        reason: 'Unable to validate email address. Please try again.'
+      };
+    }
+
+    return data as EmailValidationResult;
+  } catch (error) {
+    console.error('Email validation exception:', error);
+    return {
+      valid: false,
+      reason: 'Unable to validate email address. Please try again.'
+    };
+  }
+}