Refactor: update API_BASE_URL assignment to use type assertion

Author: medevs

frontend/app/admin/page.tsx

@@ -25,7 +25,7 @@ import { Input } from "@/components/ui/input";
 import { Skeleton } from "@/components/ui/skeleton";
 import { api, DocumentInfo, KBStats, HealthStatus, isAdminKeyConfigured } from "@/lib/api";
 
-const API_BASE_URL = process.env.NEXT_PUBLIC_API_URL || "http://localhost:8000";
+const API_BASE_URL = process.env.NEXT_PUBLIC_API_URL  as string;
 
 /**
  * Validates an API key by making a test request to the backend

frontend/hooks/useChat.ts

@@ -5,7 +5,7 @@
 import { useState, useRef, useEffect, useCallback } from "react";
 import { ChatMessage } from "@/types";
 
-const API_BASE_URL = process.env.NEXT_PUBLIC_API_URL || "http://localhost:8000";
+const API_BASE_URL = process.env.NEXT_PUBLIC_API_URL as string;
 
 interface UseChatOptions {
   initialMessages?: ChatMessage[];

frontend/lib/api.ts

@@ -7,7 +7,7 @@
  * - Set NEXT_PUBLIC_ADMIN_API_KEY in .env.local
  */
 
-const API_BASE_URL = process.env.NEXT_PUBLIC_API_URL || "http://localhost:8000";
+const API_BASE_URL = process.env.NEXT_PUBLIC_API_URL as string;
 
 // Admin API key from environment (required for admin operations)
 const ADMIN_API_KEY = process.env.NEXT_PUBLIC_ADMIN_API_KEY || "";