docs: Improve docs with core-concept and guides

apps/wiki/source.config.ts

@@ -4,6 +4,11 @@ import {remarkReplaceEnv} from './lib/remark-replace-env.mjs';
 // Options: https://fumadocs.vercel.app/docs/mdx/collections#define-docs
 export const docs = defineDocs({
   dir: 'content/docs',
+  docs: {
+    postprocess: {
+      includeProcessedMarkdown: true,
+    },
+  },
 });
 
 export default defineConfig({