refactor: migrated to next 16, updated fumadocs

- Deleted the empty middleware file as it was temporarily disabled for client-side i18n implementation.
- Updated `next`, `next-intl`, and `fumadocs` packages to their latest versions.
- Cleaned up the `next.config.ts` by removing the eslint configuration.
- Enhanced `tsconfig.json` with additional paths for `fumadocs-mdx`.
- Adjusted imports in `layout.tsx` and `request.ts` for better structure and functionality.

surfsense_web/source.config.ts

@@ -1,5 +1,7 @@
-import { defineDocs } from "fumadocs-mdx/config";
+import { defineDocs, defineConfig } from "fumadocs-mdx/config";
 
 export const docs = defineDocs({
 	dir: "content/docs",
 });
+
+export default defineConfig();