ci: add site deployment action

.github/workflows/deploy.yml

@@ -0,0 +1,44 @@
+name: Deploy Quartz site to GitHub Pages using Nix
+
+on:
+  push:
+    branches:
+      - main
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: "pages"
+  cancel-in-progress: false
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0 # Fetch all history for git info
+      - name: Install Nix
+        uses: DeterminateSystems/nix-installer-action@main
+      - name: Activate Magic Cache
+        uses: DeterminateSystems/magic-nix-cache-action@main
+      - name: Build site
+        run: nix build
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: result/public
+
+  deploy:
+    needs: build
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4