Remove coverage pragmas and fix path typing

[lydakis]

Summary

• drop the remaining pragma: no cover comments and bogus type-checker guards so regular type hints can be used instead
• add the necessary TYPE_CHECKING imports and casts so the VFS path resolver mixin exposes the attributes mypy expects without any overrides
• run the repo pre-commit hook suite to ensure Ruff formatting and mypy all pass after the cleanup

Testing

• uv run pytest
• uv run pre-commit run --all-files

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Codex Task