feat: add Python 3.14 support to CI, CLI schema, and package classifiers

[ofir-frd]

Problem

Python 3.14 support is incomplete in several places. Closes #5253.

The test CI matrices (_test.yml, _test_langgraph.yml, _integration_test.yml) already include 3.14 on main, but the following gaps remain:

• ci.yml schema-check job: matrix only lists 3.13 and hardcodes python-version: "3.13" in the setup step
• generate_schema.py: python_version enum stops at "3.13"
• schema.json / schema.v0.json: same gap; both also missing trailing newline
• cli.py help text: still lists 3.11, 3.12, or 3.13
• libs/langgraph/pyproject.toml: no Python :: 3.14 classifier
• libs/prebuilt/pyproject.toml: same

Solution

8 files changed, 17 insertions, 8 deletions — all additive, no breaking changes.

File	Change
.github/workflows/ci.yml	Add "3.14" to schema-check matrix; fix hardcoded python-version: "3.13" → ${{ matrix.python-version }}
libs/cli/generate_schema.py	Add "3.14" to python_version enum
libs/cli/schemas/schema.json	Add "3.14" to enum; fix missing trailing newline
libs/cli/schemas/schema.v0.json	Same as above
libs/cli/langgraph_cli/cli.py	Update help text to include 3.14
libs/langgraph/pyproject.toml	Add Programming Language :: Python :: 3.14 classifier
libs/prebuilt/pyproject.toml	Same
libs/cli/tests/unit_tests/test_config.py	Add "3.14" to test_validate_config, test_docker_tag_different_python_versions_with_distro, and test_docker_tag_with_api_version

Notes

• Schema version unchanged: "version": "v0" is preserved — adding a new enum value is backward-compatible and does not warrant a version bump
• MIN_PYTHON_VERSION / DEFAULT_PYTHON_VERSION unchanged: validation in config.py uses a minimum version check (>= 3.11), so 3.14 passes automatically
• Checkpoint packages: libs/checkpoint, libs/checkpoint-postgres, libs/checkpoint-sqlite do not have Python version classifiers, so no changes needed there

Testing

The CI test matrices (_test.yml / _test_langgraph.yml) already cover Python 3.14 on main. With this PR, the schema-check job will also validate against 3.14. The updated test_config.py tests confirm 3.14 passes validate_config and generates the correct Docker tags.

🤖 Generated with Claude Code