Refactor route handlers and CMS clients

Refactored the route handlers to use a new `enhanceRouteHandler` function for better control over request handlers and user authentication. CMS clients are now created using factory functions for better encapsulation and control over instance creation. Renamed `client.ts` in 'keystatic' to `keystatic-client.ts`.

apps/web/app/api/db/webhook/route.ts

@@ -1,18 +1,21 @@
 import { getDatabaseWebhookHandlerService } from '@kit/database-webhooks';
+import { enhanceRouteHandler } from '@kit/next/routes';
 
 /**
  * @name POST
  * @description POST handler for the webhook route that handles the webhook event
  */
-export async function POST(request: Request) {
+export const POST = enhanceRouteHandler(async ({ request }) => {
   const service = getDatabaseWebhookHandlerService();
 
   try {
     // handle the webhook event
     await service.handleWebhook(request);
 
+    // return a successful response
     return new Response(null, { status: 200 });
-  } catch {
+  } catch (error) {
+    // return an error response
     return new Response(null, { status: 500 });
   }
-}
+});