Fix CI: declare Cloudflare.Env so astro check passes without wrangler types

The cloudflare:workers module types `env` as `Cloudflare.Env`, which is
populated by `wrangler types` into the gitignored `worker-configuration.d.ts`.
CI doesn't have that file, so `Env` was empty and `env.WAITLIST` failed type
checking. Previous `declare module 'cloudflare:workers'` augmentation was a
no-op because the module uses `export =` (CommonJS).

Declaring `Cloudflare.Env` directly mirrors what wrangler generates and lets
TS merge both declarations locally while keeping CI green.

Author: barckcode

src/env.d.ts

@@ -1,11 +1,14 @@
 /// <reference types="astro/client" />
 
-type RuntimeEnv = {
-  WAITLIST: KVNamespace;
-  PUBLIC_URL: string;
-};
-
-declare module 'cloudflare:workers' {
-  const env: RuntimeEnv;
-  export { env };
+// Mirrors the shape generated by `wrangler types` into
+// `worker-configuration.d.ts` (which is gitignored). Declaring it here keeps
+// CI type-checking green even when the wrangler-generated file is absent,
+// and TS will merge both declarations when it IS present locally.
+declare namespace Cloudflare {
+  interface Env {
+    WAITLIST: KVNamespace;
+    PUBLIC_URL: string;
+  }
 }
+
+interface Env extends Cloudflare.Env {}