fix(ci): deploy docs via GitHub Actions Pages pipeline

.github/workflows/docs.yml

@@ -7,17 +7,64 @@ on:
       - 'docs/**'
       - 'mkdocs.yml'
       - 'README.md'
+      - '.github/workflows/docs.yml'
+  pull_request:
+    paths:
+      - 'docs/**'
+      - 'mkdocs.yml'
+      - 'README.md'
+      - '.github/workflows/docs.yml'
   workflow_dispatch:
 
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: pages
+  cancel-in-progress: false
+
 jobs:
-  deploy:
+  build:
+    name: Build MkDocs site
     runs-on: ubuntu-latest
-    permissions:
-      contents: write
     steps:
-      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
-      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
+      - name: Checkout
+        uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+
+      - name: Setup Python
+        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: '3.x'
-      - run: pip install mkdocs-material
-      - run: mkdocs gh-deploy --force
+
+      - name: Install MkDocs Material
+        run: |
+          set -euo pipefail
+          python3 -m pip install --upgrade pip
+          python3 -m pip install mkdocs mkdocs-material
+
+      - name: Build site (strict)
+        run: mkdocs build --strict --site-dir site
+
+      - name: Upload Pages artifact
+        if: github.ref == 'refs/heads/main'
+        uses: actions/upload-pages-artifact@fc324d3547104276b827a68afc52ff2a11cc49c9 # v5.0.0
+        with:
+          path: site
+
+  deploy:
+    name: Deploy to GitHub Pages
+    if: github.ref == 'refs/heads/main'
+    needs: build
+    runs-on: ubuntu-latest
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
+      - name: Setup Pages
+        uses: actions/configure-pages@45bfe0192ca1faeb007ade9deae92b16b8254a0d # v6.0.0
+
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@cd2ce8fcbc39b97be8ca5fce6e763baed58fa128 # v5.0.0