[Prevent Spec Implementation Details] Add guardrails to prevent implementation details in Spec Agent #6

	# Runs automated quality checks on pull requests before merging.
	# Validates code quality by running extension unit tests and chatmode file linting.
	# Serves as a quality gate to prevent broken code or oversized chatmode files from being merged.
	name: PR Checks

	on:
	pull_request:
	branches:
	- main
	- 'feature/**'
	paths:
	- 'vscode-extension/**'
	- '.github/chatmodes/**'
	- 'scripts/**'
	- '.github/workflows/pr-checks.yml'

	jobs:
	test:
	runs-on: ubuntu-latest

	steps:
	- name: Checkout code
	uses: actions/checkout@v4

	- name: Setup Node.js
	uses: actions/setup-node@v4
	with:
	node-version: '20'
	cache: 'npm'
	cache-dependency-path: \|
	vscode-extension/package-lock.json
	package-lock.json

	- name: Install root dependencies
	run: npm ci

	- name: Install extension dependencies
	working-directory: vscode-extension
	run: npm ci

	- name: Compile extension
	working-directory: vscode-extension
	run: npm run compile

	- name: Run extension unit tests
	working-directory: vscode-extension
	run: \|
	# Install xvfb for headless VS Code testing
	# xvfb provides a virtual display server, required for VS Code's Electron environment
	sudo apt-get update
	sudo apt-get install -y xvfb

	# Run tests with virtual display
	# xvfb-run -a automatically finds an available display number
	xvfb-run -a npm test
	env:
	# Prevent VS Code from showing UI during tests
	DISPLAY: ':99.0'

	- name: Lint chatmode files
	run: npm run lint:chatmode:all

	- name: PR checks summary
	if: success()
	run: \|
	echo "✅ All PR checks passed!"
	echo "- Extension unit tests: PASSED"
	echo "- Chatmode linting: PASSED"

Provide feedback