ci: specify node and python versions in workflows and root files

[hzhangxyz]

No description provided.

[Copilot]

Pull request overview

This PR standardizes Node.js and Python version specifications across the repository by adding version files for local development tools and defining version constants in CI workflows.

Changes:

• Added .python-version file specifying Python 3.14
• Added .node-version file specifying Node 24
• Introduced NODE_LATEST_VERSION environment variable in npm.yml and docs.yml workflows to centralize Node version specification

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
.python-version	Specifies Python 3.14 for local version managers like pyenv
.node-version	Specifies Node 24 for local version managers like nvm
.github/workflows/npm.yml	Adds NODE_LATEST_VERSION environment variable and uses it in setup-node action
.github/workflows/docs.yml	Adds NODE_LATEST_VERSION environment variable and uses it in setup-node action

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[Copilot]

The NODE_LATEST_VERSION environment variable is defined here and in docs.yml, but the jest.yml workflow also uses Node 24 in its test matrix without referencing this shared constant. Consider either:

1. Moving this to a reusable workflow configuration that all Node-based workflows can share
2. Updating jest.yml to also define and use NODE_LATEST_VERSION for consistency
3. Using a repository-level variable or secret that all workflows can reference

This would ensure version updates only need to be made in one place.

Suggested change

	NODE_LATEST_VERSION: 24
	NODE_LATEST_VERSION: ${{ vars.NODE_LATEST_VERSION }}

[Copilot]

The NODE_LATEST_VERSION environment variable is duplicated here and in npm.yml. This creates a maintenance burden where version updates must be made in multiple places. Consider using a repository-level variable or a reusable workflow configuration to centralize this value across all workflows.