Drop Python 3.9 support, require Python 3.10+

[Copilot]

Updates minimum Python version from 3.9 to 3.10.

Changes

• pyproject.toml: Python dependency ^3.9 → ^3.10, ruff target py39 → py310
• CI/CD: Removed Python 3.9 from GitHub Actions and Travis CI test matrices
• README: Updated requirements section
• Linting: Added UP007 and UP038 to ruff ignore list to preserve existing Optional[X] and isinstance((X, Y)) patterns

Original prompt

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This section details on the original issue you should resolve

<issue_title>Python 3.9のサポートを廃止する</issue_title>
<issue_description></issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Python 3.9のサポートを廃止する #102

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[kci-pr-agent]

Title

Drop Python 3.9 support, require Python 3.10+

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Description

• CIテストマトリクスからPython3.9を除外

• pyproject.tomlでPython要件を^3.10に更新

• ruff target-versionをpy310に変更

• ruff ignoreリストにUP007とUP038を追加

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Changes walkthrough 📝

	Relevant files
Configuration changes	lint-test.yml テストマトリクスからPython3.9除外                                                                        .github/workflows/lint-test.yml GitHub ActionsのテストマトリクスからPython3.9を削除 +1/-1      .travis.yml Travis CIからPython3.9削除                                                                      .travis.yml Travis CIのテストマトリクスからPython3.9を削除 +0/-1      pyproject.toml Pythonバージョンとlint設定更新                                                                          pyproject.toml Python依存を^3.9から^3.10に変更 ruffのtarget-versionをpy39からpy310に更新 ruff ignoreリストにUP007とUP038を追加 +4/-3
Documentation	README.md ドキュメント要件を3.10+に更新                                                                                README.md 必要Pythonバージョンを3.9+から3.10+に更新 +1/-1

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PR Reviewer Guide 🔍

Here are some key observations to aid the review process:

🎫 Ticket compliance analysis ✅ 102 - PR Code Verified Compliant requirements: Python 3.9のサポート廃止 pyproject.tomlのバージョン更新 READMEのRequirements更新 CI/CDマトリクスから3.9削除 ruff target-versionの更新 UP007, UP038のignore追加 Requires further human verification: CI/CD上でのテスト実行結果確認

⏱️ Estimated effort to review: 2 🔵🔵⚪⚪⚪

🧪 No relevant tests

🔒 No security concerns identified

⚡ No major issues detected

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[Copilot]

Pull request overview

This PR drops support for Python 3.9 and sets the minimum required version to Python 3.10+, updating all related configuration files and CI/CD pipelines accordingly.

• Updated Python dependency from ^3.9 to ^3.10 across the project
• Removed Python 3.9 from test matrices in GitHub Actions and Travis CI
• Added ruff ignore rules (UP007, UP038) to preserve existing code style patterns

Reviewed changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
pyproject.toml	Updated Python version requirement to ^3.10, changed ruff target to py310, added UP007/UP038 ignore rules, removed outdated comment about keep-runtime-typing
poetry.lock	Regenerated lock file with Poetry 1.8.5 for Python 3.10+, removed Python 3.9-specific dependency markers
README.md	Updated requirements documentation from Python 3.9+ to Python 3.10+
.travis.yml	Removed Python 3.9 from test matrix
.github/workflows/lint-test.yml	Removed Python 3.9 from test matrix

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[Copilot]

The comment that was removed stated that keep-runtime-typing would no longer be necessary once Python 3.9 support is dropped. However, the setting is still being kept. The comment should be updated rather than removed to explain that the setting is now being maintained for code style consistency rather than Python 3.9 compatibility. Consider updating the comment to reflect the current reasoning, such as: "既存のコードスタイル（Optional[X]など）を維持するため、この設定を使用する" (Using this setting to maintain existing code style such as Optional[X]).

Suggested change

	# 以下のエラーが発生しないようにする。
	# 既存のコードスタイル（Optional[X]など）を維持するため、この設定を使用する