why:
- Snapshot classes have properties that conflict with dataclass field names during type checking
- These property/field collisions cause mypy to generate false positive error messages
- We need to silence these specific errors without compromising overall type safety

what:
- Added [[tool.mypy.overrides]] section in pyproject.toml for libtmux.snapshot module
- Set disable_error_code = ["override"] to silence property override errors
- Placed the override in a module-specific section to limit scope and prevent disabling
  this error check for other modules

refs: Complements the snapshot class refactoring to ensure clean mypy checks