[Docs Site] Re-add CI.yml workflow

.github/workflows/ci.yml

@@ -0,0 +1,44 @@
+name: CI
+
+on:
+  pull_request:
+    branches:
+      - production
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  compile:
+    name: Compiles
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 1
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 22
+
+      - name: Get npm cache directory
+        id: npm-cache-dir
+        shell: bash
+        run: echo "dir=$(npm config get cache)" >> ${GITHUB_OUTPUT}
+
+      - uses: actions/cache@v4
+        id: npm-cache
+        with:
+          path: ${{ steps.npm-cache-dir.outputs.dir }}
+          key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
+          restore-keys: |
+            ${{ runner.os }}-node-
+
+      - run: npm ci
+
+      - run: npx astro build
+        env:
+          NODE_OPTIONS: "--max-old-space-size=4192"
+
+      - name: Check - Validate redirects (infinite loops, sources with fragment)
+        run: npx tsm bin/validate-redirects.ts