Configuration value types

Ensure configuration values use appropriate types, avoid unnecessary Optional annotations, and maintain consistency in data formats and units.

Key principles:

1. Use explicit boolean types instead of string representations when the configuration is consumed as a boolean
2. Avoid Optional for fields with defaults - if a default value is provided, Optional is redundant
3. Choose consistent time units across related configurations (prefer seconds for precision, minutes for readability)
4. Use appropriate data formats - prefer unix timestamps over ISO strings for simplicity and timezone safety

Example of proper configuration typing:

class MyConfig(BaseSettings):
    # Good: explicit boolean with default
    SSL_VERIFY: bool = Field(default=True)
    
    # Bad: unnecessary Optional with default
    # SSL_VERIFY: Optional[bool] = Field(default=True)
    
    # Good: consistent time unit choice
    ACCESS_TOKEN_EXPIRE_MINUTES: int = Field(default=30)
    
    # Good: unix timestamp for cache keys
    def get_cache_timestamp(self) -> int:
        return int(datetime.now().timestamp())

This approach reduces configuration complexity, improves type safety, and ensures consistent behavior across different deployment environments.