- Add stripe_payment_intent_id field to WalletTransaction model with proper defaults
- Update User.deduct_balance() to handle missing stripe_payment_intent_id gracefully
- Update User.add_balance() to handle missing stripe_payment_intent_id gracefully
- Use try-catch pattern to handle database schema mismatches
- Provide empty string as default for stripe_payment_intent_id when field is required
Issue: Database has NOT NULL constraint on stripe_payment_intent_id but code doesn't provide it
Solution: Add field with proper defaults and graceful error handling
Prevents: 'NOT NULL constraint failed: wallet_wallettransaction.stripe_payment_intent_id'
