fix: remove basePath for custom domain compatibility

basePath was set to "/markbloom" for GitHub Pages subdirectory hosting,
but it breaks asset loading when using a custom domain (root-served).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: mertguvencli

next.config.ts

@@ -1,10 +1,7 @@
 import type { NextConfig } from "next";
 
-const isProd = process.env.NODE_ENV === "production";
-
 const nextConfig: NextConfig = {
   output: "export",
-  basePath: isProd ? "/markbloom" : "",
   images: {
     unoptimized: true,
   },