Update Rust crates and Python dev dependency floors

[w-martin]

Summary

• Rust: cargo update for semver-compatible bumps, plus major bumps for toml (0.8→1.1), criterion (0.5→0.8), and the ruff_python_* git dependencies (tag 0.15.0→0.16.2, the internal ruff crates this checker's parser is built on).
• Python: bumped dev/docs dependency-group floors to current releases, including major jumps (mypy 1→2, pyrefly 0.x→1.x, invoke 2→3, complexipy 5→6, pyarrow 23→25, mkdocstrings-python 1→2). licensecheck stayed at 2025.1.0 since the 2026.x series requires Python ≥3.12, which conflicts with this project's >=3.11 floor. The optional-dependencies floors (pandas, pandera, polars — this library's own supported-version promise to its users) were deliberately left alone, since that's a compatibility policy decision separate from dev-tooling freshness.
• ruff 0.16 enables far more default rules; added CPY001 (copyright-header) to the ignore list since this project has never used copyright headers.
• ruff 0.16 also formats Python code blocks embedded in Markdown by default, which reformatted 17 docs/example files (cosmetic quote-style/spacing only).
• Fixed a pre-existing, unrelated bug found along the way: rust/benches/parser_bench.rs had one extra ../ in its include_str! path, so cargo build --benches / cargo bench failed unconditionally on main.

Test plan

• cargo build / cargo test (154 tests) / cargo clippy -- -D warnings / cargo fmt --check / cargo bench (now compiles and runs)
• ruff check . / ruff format --check . / ty check .
• bandit, complexipy, pip-audit (no known vulnerabilities)
• mkdocs build --strict
• Full pytest suite (299 tests) + coverage threshold, including the mypy-plugin tests against mypy 2.x