chore: repo refresh (2026-09)

[tlambert03]

Routine tooling refresh, one commit per step.

ci: autoupdate pre-commit hooks

• pre-commit/pre-commit-hooks: v5.0.0 → v6.0.0
• astral-sh/ruff-pre-commit: v0.9.9 → v0.16.9
• pre-commit/mirrors-mypy: v1.15.0 → v2.3.1

All hooks pass with the new versions; no lint fixes were needed.

ci: bump GitHub Actions

• actions/checkout: v2/v4 → v7
• astral-sh/setup-uv: v6 → v7
• codecov/codecov-action: v5 → v7
• softprops/action-gh-release: v2 → v3

These major bumps mostly move the actions to the Node 24 runtime. None of the inputs this workflow passes were removed or changed (setup-uv v7 dropped server-url, which isn't used here). pypa/gh-action-pypi-publish@release/v1 is left as is because it's a branch ref.

chore: drop Python 3.9, add 3.14 and 3.15 (RC)

• requires-python = ">=3.10", ruff target-version = "py310"
• Classifiers: removed 3.9, added 3.14 and 3.15
• CI matrix (full grid across all 3 OSes): 3.10–3.15

refactor: modernize syntax for Python >= 3.10

• ruff UP035: import Callable from collections.abc instead of typing

Decisions

• 3.9 dropped: it reached EOL on 2025-10-31.
• 3.10 kept: its EOL is 2026-10-31. The maintainer chose to keep it for this refresh.
• 3.14 added.
• 3.15 is a release candidate (final planned for 2026-10-01). It is added as a bare "3.15", which setup-uv resolves to the RC when no final release is available. Because the matrix is a full grid, it runs on all OSes.
• The typing_extensions; python_version < '3.13' marker is still needed at a 3.10 minimum, so it stays.

Needs attention

• The pre-commit config still uses the hook id ruff, which ruff now reports as "(legacy alias)" for ruff-check. It still works; renaming it is optional.

🤖 Generated with Claude Code

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.73%. Comparing base (d30f274) to head (f86c0d0).
⚠️ Report is 8 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #16      +/-   ##
==========================================
- Coverage   92.94%   92.73%   -0.21%     
==========================================
  Files           2        2              
  Lines         170      179       +9     
==========================================
+ Hits          158      166       +8     
- Misses         12       13       +1     

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