fix: Add nixpacks configuration for Astro deployment

dealplustech-astro/node_modules/astro/dist/env/config.d.ts

@@ -0,0 +1,10 @@
+import type { BooleanField, BooleanFieldInput, EnumField, EnumFieldInput, NumberField, NumberFieldInput, StringField, StringFieldInput } from './schema.js';
+/**
+ * Return a valid env field to use in this Astro config for `env.schema`.
+ */
+export declare const envField: {
+    string: (options: StringFieldInput) => StringField;
+    number: (options: NumberFieldInput) => NumberField;
+    boolean: (options: BooleanFieldInput) => BooleanField;
+    enum: <T extends string>(options: EnumFieldInput<T>) => EnumField;
+};