Documentation Updates (#79)

* Docs: Added Shadcn sidebar; added algorithm to automatically infer parents without needing to specify it.
* Extracted Markdoc compilation in a separate file
* Site Navigation: simplify nav by removing the border
* Docs Navigation: added TOC; improved layout on mobile

apps/web/app/(marketing)/docs/loading.tsx

@@ -0,0 +1,3 @@
+import { GlobalLoader } from '@kit/ui/global-loader';
+
+export default GlobalLoader;