/hathor-blueprint

Review `blueprints/token_vault.py` as if it were going into a pull request.

Return the review using this format:
1. Import compliance
2. Class and export compliance
3. Persistent field compliance
4. Method decorator compliance
5. Context usage risks
6. Deposit action risks
7. Withdrawal action risks
8. View method safety
9. Unsupported syntax or builtin risks
10. Required changes before validation
