fix: Add nixpacks configuration for Astro deployment

dealplustech-astro/node_modules/astro/dist/container/vite-plugin-container.js

@@ -0,0 +1,15 @@
+const virtualModuleId = "astro:container";
+function astroContainer() {
+  return {
+    name: "astro:container",
+    enforce: "pre",
+    resolveId(id) {
+      if (id === virtualModuleId) {
+        return this.resolve("astro/virtual-modules/container.js");
+      }
+    }
+  };
+}
+export {
+  astroContainer as default
+};