chore[mypy]: Add snapshot module override

why: The snapshot classes use frozen_dataclass_sealable decorator which
     adds the seal method at runtime, but mypy cannot detect this
     during static analysis.

what:
- Add a mypy override in pyproject.toml to disable 'misc' and
  'unused-ignore' error codes specifically for libtmux.snapshot
- This allows proper typing without creating false errors from mypy
  while preserving the runtime functionality

Author: tony

pyproject.toml

@@ -149,6 +149,10 @@ ignore_errors = true
 module = "tests.examples._internal.frozen_dataclass_sealable.test_basic"
 ignore_errors = true
 
+[[tool.mypy.overrides]]
+module = "libtmux.snapshot"
+disable_error_code = ["misc", "unused-ignore"]
+
 [tool.coverage.run]
 branch = true
 parallel = true