fix(python): clear ruff findings and pin the linter to a minor series

[yfedoseev]

Why every dependabot PR is red

The Lint and Format Check job (.github/workflows/python.yml:120) runs uv run ruff check python/ and reports "Found 31 errors" — on every open PR, including bumps that touch no Python at all. It fails identically on a Rust-only bump (#117) and a CI-action-only bump (#101), which is what shows it isn't the bumps.

The cause is the dependency declaration, not the code:

dev = ["maturin>=1.0", "pytest>=7.0", "ruff>=0.4"]

Unpinned, so CI resolves whatever ruff published most recently — 0.16.4 today — and each release turns on new default rules. The gate changed under the repo with no commit, and all 11 open dependabot PRs went red together. (Locally I had ruff 0.14.6 and ruff check python/ passed, which is exactly how this stayed invisible.)

What's in here

1. Fix the 31 findings. 29 were in the _native.pyi stub:

rule	fix
PYI044	drop from __future__ import annotations — no effect in stubs
PYI026 ×3	give FormatName / _Path / _CellValue an explicit TypeAlias
UP037 + PYI020 ×5	unquote the forward references
PYI034 ×2	__enter__ returns Self
PYI036 ×2, UP045 ×7, UP006 ×2, UP007 ×2	`type[BaseException]

PEP 604/585 syntax appears only in the stub, where it's valid regardless of the requires-python = ">=3.8" runtime floor — stubs aren't evaluated at runtime. The remaining 2 findings were import and __all__ ordering in __init__.py (auto-fixed).

2. Pin ruff>=0.16,<0.17 so a future release can't silently redden every open PR again. Comment in pyproject.toml says why, so nobody widens it back.

Verification

$ uv run --group dev ruff check python/     # the exact CI command
All checks passed!

$ uv run --with mypy mypy python/office_oxide/_native.pyi
Success: no issues found in 1 source file

Also checked that every name in __all__ still resolves to an import from _native after the reordering, and that both files parse. No runtime code changed beyond import/__all__ order; the stub is never imported at runtime.

Effect

This should unblock #101, #105, #106, #107, #108, #109, #112, #113, #114, #117 and #121 in one go. #105–#108 additionally carry stale August-12 runs that will want a re-run once this lands.

https://claude.ai/code/session_01QCzrWMwEUtN6B3pN1HSKbb

[yfedoseev]

Correction to the "Effect" section above. Clearing ruff is necessary but not sufficient.

The Lint and Format Check job runs cargo fmt → cargo clippy --features python --all-targets -- -D warnings → uv run ruff check python/, in that order. Rust 1.98's clippy added chunks_exact_to_as_chunks, which fires twice on main — so the job has been failing at the clippy step and never reaching ruff at all. The "Found 31 errors" output I quoted came from an August-12 run, back when the toolchain still got past clippy.

So this PR fixes the ruff half; #124 fixes the clippy half. Both are needed before the 11 dependabot PRs go green.

Verified on main with no changes applied:

$ cargo clippy --workspace --all-targets -- -D warnings
error: using `chunks_exact` with a constant chunk size  --> src/cfb/reader.rs:43:18
error: using `chunks_exact` with a constant chunk size  --> src/ppt/text.rs:379:10