Require Python 3.14

[cjunius]

Summary

Bumps the project to Python 3.14 only.

• requires-python = ">=3.14"; classifiers, ruff target-version = py314,
  mypy python_version = 3.14
• CI (ci.yml) lint job and test matrix both run on 3.14 (3.12 / 3.13 dropped)
• README badge / "Requires" line, CONTRIBUTING, CLAUDE.md, CHANGELOG updated

ruff-applied py314 idioms

Retargeting ruff to py314 auto-fixed two spots (both valid 3.14+ syntax):

• src/pychess/__main__.py: except (IndexError, FileNotFoundError, OSError):
  → except IndexError, FileNotFoundError, OSError: (PEP 758 — parentheses no
  longer required)
• src/pychess/eval_board.py: -> "EvalBoard" → -> EvalBoard (safe under
  PEP 649 deferred annotation evaluation)

Tooling sync

.pre-commit-config.yaml hook revs were stale vs pyproject.toml; bumped to
match (ruff 0.16.4, mypy 2.3.1, chess 1.11.2, pytest 9.1.1).

Testing

On Python 3.14.7: ruff check, ruff format --check, mypy (strict),
pytest (80 pass, 91% coverage), pre-commit, and a UCI end-to-end search all
green.

On Linux, 3.14 changes the multiprocessing default from fork to forkserver.
The Lazy SMP worker already assumes spawn-style semantics (pickled payloads,
re-imports, shared memory attached by name), so forkserver is fine — CI will
confirm on Linux.

Checklist

• ruff check . and ruff format --check . pass
• mypy passes (strict on src/)
• pytest passes; coverage stays >= 85%
• Tests added or updated for the change — n/a
• CHANGELOG.md updated under ## [Unreleased]
• README.md / docs/*.md updated

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Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ All tests successful. No failed tests found.

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[Copilot]

🟢 Approval recommended

The changes consistently apply the Python 3.14 baseline across packaging, CI, and docs without introducing any verified functional or typing issues in the modified code paths.

Pull request overview

This PR updates pychess to require Python 3.14+ across packaging metadata, CI, and contributor-facing documentation, and aligns formatting/linting/type-check tooling to the same baseline.

Changes:

• Raise the project’s minimum supported Python to 3.14 (requires-python, classifiers, ruff target version, mypy python_version).
• Update CI to run lint/type-check/test only on Python 3.14.
• Sync docs and pre-commit hook versions with the new tooling pins, and apply a couple of 3.14-only syntax/typing idioms.

File summaries

File	Description
src/pychess/eval_board.py	Uses 3.14+ annotation behavior to drop a quoted forward reference in EvalBoard.copy()’s return type.
src/pychess/main.py	Adopts 3.14+ except syntax for multiple exception types (no parentheses).
README.md	Updates Python support badge and “Requires Python …” wording to 3.14+.
pyproject.toml	Enforces Python 3.14 minimum and retargets ruff/mypy configuration accordingly.
CONTRIBUTING.md	Updates venv setup instructions to use python3.14.
CLAUDE.md	Updates the agent guide to reflect Python 3.14+ and CI running on 3.14.
CHANGELOG.md	Notes the new Python 3.14 requirement under Unreleased changes.
.pre-commit-config.yaml	Bumps pre-commit hook revs / deps to match pyproject.toml pins.
.github/workflows/ci.yml	Updates lint job and test matrix to run only on Python 3.14.

Review details

• Files reviewed: 9/9 changed files
• Comments generated: 0
• Review effort level: Lite

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