feat(toc): implement post table of contents and refactor line number component

env.d.ts

@@ -1,10 +1,12 @@
 /// <reference types="vite/client" />
 import type { Alpine } from "alpinejs";
+import type { TocManager } from "./src/alpine/toc";
 
 export {};
 
 declare global {
   interface Window {
     Alpine: Alpine;
+    tocManager?: TocManager;
   }
 }