chore: add types for env file

Author: steveoh

src/vite-env.d.ts

@@ -1 +1,12 @@
 /// <reference types="vite/client" />
+
+interface ImportMetaEnv {
+  readonly VITE_WEB_API: string;
+  readonly VITE_DISCOVER: string;
+  readonly VITE_FIREBASE_CONFIG: string;
+  readonly PACKAGE_VERSION: string;
+}
+
+interface ImportMeta {
+  readonly env: ImportMetaEnv;
+}