docs: Claude Code v2.1.278 - AGENTS.md support, TaskOutput removed, claude-mythos model family - #1300

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4, actions/create-github-app-token@v2. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

The process '/usr/bin/git' failed with exit code 128

No file matched to [/home/runner/work/claude-code-docs/claude-code-docs/**/*requirements*.txt,/home/runner/work/claude-code-docs/claude-code-docs/**/*requirements*.in,/home/runner/work/claude-code-docs/claude-code-docs/**/*constraints*.txt,/home/runner/work/claude-code-docs/claude-code-docs/**/*constraints*.in,/home/runner/work/claude-code-docs/claude-code-docs/**/pyproject.toml,/home/runner/work/claude-code-docs/claude-code-docs/**/uv.lock,/home/runner/work/claude-code-docs/claude-code-docs/**/*.py.lock]. The cache will never get invalidated. Make sure you have checked out the target repository and configured the cache-dependency-glob input correctly.