refactor: use environment variable for GHOST_API_KEY

Replace hardcoded GHOST_API_KEY with process.env.GHOST_API_KEY in 
API routes to enhance security. Update Docker commands in the CI 
workflow to pass the GHOST_API_KEY as an environment variable. 
Add GHOST_API_KEY to the Next.js configuration for consistent 
access across the application.

app/api/fetchProject/route.tsx

@@ -3,7 +3,7 @@ import { NextResponse } from "next/server";
 export const runtime = "nodejs"; // Force Node runtime
 
 const GHOST_API_URL = "http://192.168.179.31:2368";
-const GHOST_API_KEY = "067b8434f2e7f2a771dfcc45a7"; // Replace with your actual key
+const GHOST_API_KEY = process.env.GHOST_API_KEY;
 
 export async function GET(request: Request) {
   const { searchParams } = new URL(request.url);