feat(update): add docker image version updater CLI, workflow, and lint tests

- Add utils/docker/version_updater.py with CLI for updating Docker image versions
- Add cli/fix/docker_image_versions module wrapping the updater
- Add .github/workflows/update.yml replacing update-skills.yml
- Add scripts/github/ helpers: check_git_changes, install_update_python, open_update_pr, update_docker_image_versions
- Add tests/lint/filesystem/ for scripts/ and utils/ folder file-type enforcement
- Add tests/lint/ansible/ for legacy module usage and vars usage checks
- Reorganize tests/lint/repository/ and move test_vars_usage_in_yaml.py to ansible/
- Add artefact docs: files/github/workflow.md, scripst.md, utils.md
- Apply documentation.md standards to all modified markdown files

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/github/install_update_python.sh

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+python3 -m pip install --upgrade pip
+python3 -m pip install PyYAML