feat(billing): add missing payment methods and configurations

- Added migration to include global payment method configurations for Stripe and PayPal (both disabled).
- Ensured existing payment methods like bank transfer and manual payment are correctly configured.
- Added database constraints and indexes for improved data integrity in billing models.
- Introduced foreign key relationship between CreditTransaction and Payment models.
- Added webhook configuration fields to PaymentMethodConfig for future payment gateway integrations.
- Updated SignUpFormUnified component to handle payment method selection based on user country and plan.
- Implemented PaymentHistory component to display user's payment history with status indicators.

frontend/src/store/authStore.ts

@@ -233,8 +233,45 @@ export const useAuthStore = create<AuthState>()(
           const tokens = responseData.tokens || {};
           const userData = responseData.user || data.user;
 
-          const newToken = tokens.access || responseData.access || data.access || null;
-          const newRefreshToken = tokens.refresh || responseData.refresh || data.refresh || null;
+          // Extract tokens with multiple fallbacks
+          // Response format: { success: true, data: { user: {...}, tokens: { access, refresh } } }
+          const newToken = 
+            tokens.access || 
+            responseData.access || 
+            data.access || 
+            data.data?.tokens?.access ||
+            data.tokens?.access || 
+            null;
+            
+          const newRefreshToken = 
+            tokens.refresh || 
+            responseData.refresh || 
+            data.refresh || 
+            data.data?.tokens?.refresh ||
+            data.tokens?.refresh || 
+            null;
+
+          console.log('Registration response parsed:', {
+            hasUserData: !!userData,
+            hasAccessToken: !!newToken,
+            hasRefreshToken: !!newRefreshToken,
+            userEmail: userData?.email,
+            accountId: userData?.account?.id,
+            tokensLocation: tokens.access ? 'tokens.access' : 
+                           responseData.access ? 'responseData.access' :
+                           data.data?.tokens?.access ? 'data.data.tokens.access' : 'not found'
+          });
+
+          if (!newToken || !userData) {
+            console.error('Registration succeeded but missing critical data:', {
+              token: newToken,
+              user: userData,
+              fullResponse: data,
+              parsedTokens: tokens,
+              parsedResponseData: responseData
+            });
+            throw new Error('Registration completed but authentication failed. Please try logging in.');
+          }
 
           // CRITICAL: Set auth state AND immediately persist to localStorage
           // This prevents race conditions where navigation happens before persist
@@ -268,8 +305,11 @@ export const useAuthStore = create<AuthState>()(
             if (newRefreshToken) {
               localStorage.setItem('refresh_token', newRefreshToken);
             }
+            
+            console.log('Auth state persisted to localStorage successfully');
           } catch (e) {
-            console.warn('Failed to persist auth state to localStorage:', e);
+            console.error('CRITICAL: Failed to persist auth state to localStorage:', e);
+            throw new Error('Failed to save login session. Please try again.');
           }
           
           // Return user data for success handling