Fix email system and implement OTP confirmation flow

Email System Fixes:
- Fix email sending after payment: handle-order-paid now calls send-notification
  instead of send-email-v2 directly, properly processing template variables
- Fix order_created email timing: sent immediately after order creation,
  before payment QR code generation
- Update email templates to use short order ID (8 chars) instead of full UUID
- Add working "Akses Sekarang" buttons to payment_success and access_granted emails
- Add platform_url column to platform_settings for email links

OTP Verification Flow:
- Create dedicated /confirm-otp page for users who close registration modal
- Add link in checkout modal and email to dedicated OTP page
- Update OTP email template with better copywriting and dedicated page link
- Fix send-auth-otp to fetch platform settings for dynamic brand_name and platform_url
- Auto-login users after OTP verification in checkout flow

Admin Features:
- Add delete user functionality with cascade deletion of all related data
- Update IntegrasiTab to read/write email settings from platform_settings only
- Add test email template for email configuration testing

Cleanup:
- Remove obsolete send-consultation-reminder and send-test-email functions
- Update send-email-v2 to read email config from platform_settings
- Remove footer links (Ubah Preferensi/Unsubscribe) from email templates

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

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/hooks/useAuth.tsx

@@ -107,37 +107,23 @@ export function AuthProvider({ children }: { children: ReactNode }) {
 
   const sendAuthOTP = async (userId: string, email: string) => {
     try {
-      const { data: { session } } = await supabase.auth.getSession();
-      const token = session?.access_token || import.meta.env.VITE_SUPABASE_ANON_KEY;
+      const { data, error } = await supabase.functions.invoke('send-auth-otp', {
+        body: { user_id: userId, email }
+      });
 
-      console.log('Sending OTP request', { userId, email, hasSession: !!session });
-
-      const response = await fetch(
-        `${import.meta.env.VITE_SUPABASE_URL}/functions/v1/send-auth-otp`,
-        {
-          method: 'POST',
-          headers: {
-            'Authorization': `Bearer ${token}`,
-            'Content-Type': 'application/json',
-          },
-          body: JSON.stringify({ user_id: userId, email }),
-        }
-      );
-
-      console.log('OTP response status:', response.status);
-
-      if (!response.ok) {
-        const errorText = await response.text();
-        console.error('OTP request failed:', response.status, errorText);
+      if (error) {
+        console.error('OTP request error:', error);
         return {
           success: false,
-          message: `HTTP ${response.status}: ${errorText}`
+          message: error.message || 'Failed to send OTP'
         };
       }
 
-      const result = await response.json();
-      console.log('OTP result:', result);
-      return result;
+      console.log('OTP result:', data);
+      return {
+        success: data?.success || false,
+        message: data?.message || 'OTP sent successfully'
+      };
     } catch (error: any) {
       console.error('Error sending OTP:', error);
       return {