feat: integrate payload cms to landing page (#25)

* feat: integrate payload cms to landing page

* feat: add payload configuration and update TypeScript target

* fix: update TypeScript paths for payload configuration

* refactor: update config import paths to use local payload.config

* fix: update quotation marks for testimonials to use HTML entities

* fix: include withPayload in Next.js plugins for proper configuration

apps/landing/src/lib/payload.ts

@@ -0,0 +1,4 @@
+import { getPayload } from 'payload';
+import config from '../payload.config';
+
+export const payload = await getPayload({ config });