Add codegen check CI job

[emilykl]

Link to issue

Closes #5680

Description of change

Adds a CI job which runs the Python codegen script and fails if the generated files do not match what's committed in the repo.

Also adds a [dev_codegen] extra in pyproject.toml which installs only the packages needed to run the codegen. This is used in the CI job. uv.lock is also updated accordingly.

This will ensure that the generated Python files (python/graph_objs/) are always up-to-date.

Testing

The job fails on this PR because the codgen files are currently out of date on v7.0.

See #5682 for a demo of the job passing and failing.

Guidelines

• I have reviewed the pull request guidelines and the Code of Conduct and confirm that this PR follows them.
• I have added an entry to the changelog if needed (not required for documentation PRs).

[Copilot]

Pull request overview

Adds a dedicated GitHub Actions workflow to ensure Plotly’s Python code-generated artifacts remain in sync with what’s committed, and introduces a focused dependency extra to run codegen in CI.

Changes:

• Add a new CI workflow that runs python commands.py codegen and fails if it produces any repo diffs.
• Introduce a dev_codegen extra in pyproject.toml to install only codegen-required dependencies (and wire it into dev_optional).
• Update uv.lock to reflect the new extra and dependency graph.

Reviewed changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated 2 comments.

File	Description
uv.lock	Adds/updates the locked dependency set to include the new dev-codegen extra.
pyproject.toml	Defines the dev_codegen extra (and updates dev_optional to include it).
.github/workflows/check-codegen.yml	New workflow to run codegen and fail CI when generated files don’t match committed files.

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