CI: update GitHub Actions to Node.js 24 compatible versions

[jensens]

Problem

All CI workflows emit deprecation warnings:

Node.js 20 actions are deprecated. The following actions are running on Node.js 20:
actions/checkout@v4, actions/setup-go@v5, actions/setup-python@v5,
golangci/golangci-lint-action@v7, astral-sh/setup-uv@v6, actions/github-script@60a0d83...

Node.js 24 will be forced starting June 2, 2026, and Node.js 20 removed September 16, 2026.

Actions to update

Current	Update to
actions/checkout@v4	actions/checkout@v5 (when available) or set FORCE_JAVASCRIPT_ACTIONS_TO_NODE24=true
actions/setup-go@v5	Check for Node 24 compatible version
actions/setup-python@v5	Check for Node 24 compatible version
golangci/golangci-lint-action@v7	Check for update
astral-sh/setup-uv@v6	Check for update
actions/github-script@60a0d83...	Pin to latest release tag

Affected workflows

• .github/workflows/ci.yml
• .github/workflows/e2e-chainsaw.yml
• .github/workflows/release.yml
• .github/workflows/docs.yaml