fix: production crash due to undefined import.meta.env by adding env utility and updating build script

src/middleware/authMiddleware.tsx

@@ -1,4 +1,5 @@
 import { redirect } from "@tanstack/react-router";
+import { VITE_PUBLIC_URL } from "../utils/env";
 
 /* ================================
  * Types
@@ -21,7 +22,7 @@ type SessionResponse = {
 
 async function fetchSession(): Promise<SessionResponse | null> {
 	try {
-		const baseURL = import.meta.env.VITE_PUBLIC_URL || window.location.origin;
+		const baseURL = VITE_PUBLIC_URL || window.location.origin;
 		const res = await fetch(`${baseURL}/api/session`, {
 			method: "GET",
 			credentials: "include",