feat: enhance exercises with quality improvements and validation tools #26

	name: Validate YAML

	on:
	push:
	branches: [main]
	paths:
	- 'skeletons/**'
	- 'exercises/**'
	- '**.yaml'
	- '**.yml'
	pull_request:
	branches: [main]
	paths:
	- 'skeletons/**'
	- 'exercises/**'
	- '**.yaml'
	- '**.yml'

	jobs:
	yamllint:
	name: YAML Lint
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v4

	- name: Install yamllint
	run: pip install yamllint

	- name: Lint skeleton YAML files
	run: \|
	yamllint -d '{extends: default, rules: {line-length: {max: 200}, truthy: disable, document-start: disable, comments-indentation: disable, indentation: {indent-sequences: whatever}, new-lines: {type: platform}}}' skeletons/

	- name: Validate YAML syntax (kubectl dry-run)
	run: \|
	echo "--- Checking YAML syntax ---"
	errors=0
	for f in skeletons/*.yaml; do
	if ! python3 -c "import yaml, sys; yaml.safe_load_all(open('$f'))" 2>/dev/null; then
	echo "INVALID: $f"
	errors=$((errors + 1))
	else
	echo "OK: $f"
	fi
	done
	if [ $errors -gt 0 ]; then
	echo "$errors file(s) failed validation"
	exit 1
	fi
	echo "All YAML files valid"

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