fix: Add missing COPPA fields to registration payload

- Added dateOfBirth, parentalEmail, and coppaConsentGiven to RegisterData interface
- Updated register function to include all required COPPA compliance fields in API payload
- Added debug logging to see registration payload
- Fixed 400 error during registration due to missing required dateOfBirth field

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

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

maternal-web/lib/auth/AuthContext.tsx

@@ -28,6 +28,9 @@ export interface RegisterData {
   password: string;
   name: string;
   role?: string;
+  dateOfBirth: string; // COPPA compliance - required
+  parentalEmail?: string; // For users 13-17
+  coppaConsentGiven?: boolean; // For users 13-17
 }
 
 interface AuthContextType {
@@ -144,13 +147,26 @@ export const AuthProvider = ({ children }: { children: ReactNode }) => {
       // Auto-detect timezone from user's device
       const detectedTimezone = Intl.DateTimeFormat().resolvedOptions().timeZone;
 
-      const response = await apiClient.post('/api/v1/auth/register', {
+      const payload: any = {
         email: data.email,
         password: data.password,
         name: data.name,
         timezone: detectedTimezone || 'UTC',
+        dateOfBirth: data.dateOfBirth,
         deviceInfo,
-      });
+      };
+
+      // Add optional COPPA fields if provided
+      if (data.parentalEmail) {
+        payload.parentalEmail = data.parentalEmail;
+      }
+      if (data.coppaConsentGiven !== undefined) {
+        payload.coppaConsentGiven = data.coppaConsentGiven;
+      }
+
+      console.log('[Auth] Registration payload:', JSON.stringify(payload, null, 2));
+
+      const response = await apiClient.post('/api/v1/auth/register', payload);
 
       // Backend returns { success, data: { user, family, tokens } }
       const { data: responseData } = response.data;