Add build action

.forgejo/workflows/build.yaml

@@ -0,0 +1,12 @@
+on:
+  push:
+    branches:
+      - main
+jobs:
+  build:
+    runs-on: build
+    steps:
+      - name: Checkout
+        uses: https://data.forgejo.org/actions/checkout@v4
+      - name: Build Astro site
+        run: npm run astro build