Bump actions/checkout from 4 to 6 #3

	name: Validate PR

	on:
	pull_request:
	branches: [main]
	types: [opened, synchronize, reopened]

	jobs:
	validate:
	runs-on: ubuntu-latest
	timeout-minutes: 10

	steps:
	- name: Checkout repository
	uses: actions/checkout@v6

	- name: Setup Node.js
	uses: actions/setup-node@v4
	with:
	node-version: '18'
	cache: 'npm'

	- name: Install dependencies
	run: npm ci

	- name: Markdown lint
	uses: DavidAnson/markdownlint-action@v1
	with:
	config: .markdownlint.json
	files: 'book/*/.md'
	globs: \|
	planning/*/.md
	README.md

	- name: Validate internal links
	run: ./scripts/validate-links.sh
	env:
	CHECK_EXTERNAL: false

	- name: Validate frontmatter schema
	run: ./scripts/validate-frontmatter.sh

	- name: Setup Python
	uses: actions/setup-python@v5
	with:
	python-version: '3.11'

	- name: Check requirement traceability
	run: python3 ./scripts/check-traceability.py

	- name: Test Mermaid rendering
	run: npm run build:mermaid

	- name: Comment PR with results
	if: always()
	uses: actions/github-script@v7
	with:
	script: \|
	const conclusion = '${{ job.status }}';
	const body = conclusion === 'success'
	? '✅ All validation checks passed!'
	: '❌ Validation failed. Check workflow logs for details.';

	github.rest.issues.createComment({
	issue_number: context.issue.number,
	owner: context.repo.owner,
	repo: context.repo.repo,
	body: `## Content Validation\n\n${body}`
	});

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