Add Biome formatter/linter and restore CI workflow (#6)

- Install Biome as the project formatter and linter
- Configure Biome with recommended settings
- Add format, lint, and check scripts to package.json
- Restore CI workflow from git history (commit 0a543e1)
- Extend CI with new Biome job for format and lint checks
- Apply Biome formatting to all TypeScript files
- Fix linting issues (use node: protocol, template literals, forEach pattern)

CI now runs on:
- All pushes to main branch
- All pull requests

Co-authored-by: Claude Sonnet 4.5 <noreply@anthropic.com>

.github/workflows/ci.yml

@@ -0,0 +1,54 @@
+name: Postgres Best Practices CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  biome:
+    name: Format and Lint (Biome)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+
+      - name: Install dependencies
+        run: npm install
+
+      - name: Run Biome CI
+        run: npm run ci:check
+
+  validate-and-build:
+    name: Validate and Build
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+
+      - name: Install dependencies
+        working-directory: packages/postgres-best-practices-build
+        run: npm install
+
+      - name: Validate rule files
+        working-directory: packages/postgres-best-practices-build
+        run: npm run validate
+
+      - name: Build AGENTS.md
+        working-directory: packages/postgres-best-practices-build
+        run: npm run build
+
+      - name: Check for uncommitted changes
+        run: |
+          if [[ -n $(git status --porcelain skills/postgres-best-practices/AGENTS.md) ]]; then
+            echo "Error: AGENTS.md is not up to date"
+            echo "Run 'npm run build' and commit the changes"
+            git diff skills/postgres-best-practices/AGENTS.md
+            exit 1
+          fi