Enhance database operations safety and code maintainability in query_proofs.py

[CreeptoGengar]

Changes Made

• Added type hints for better code maintainability and IDE support
• Implemented database connection context manager for safer DB operations
• Added custom DatabaseError exception class for better error handling
• Replaced string formatting in SQL queries with parameterized queries to prevent SQL injection
• Enhanced function documentation with detailed docstrings
• Used ProofType enum values instead of string literals
• Added proper error handling for database operations

Benefits

• Improved code safety by preventing SQL injection vulnerabilities
• Better error handling and resource management
• Enhanced code maintainability through proper typing
• Better developer experience with detailed documentation
• More robust database operations

Testing

The changes maintain backward compatibility and don't modify the existing functionality. All database operations have been tested with:

• Normal operation scenarios
• Database connection errors
• Invalid query parameters

Related Issues

N/A

Checklist

• Code follows Python type hinting best practices
• Documentation has been updated
• No breaking changes introduced
• Error handling has been improved