feat: enhance table cells with rich content support (#1409)

- Support multiple content types in table cells and headers: paragraphs, headings, lists (bullet/ordered/task), blockquotes, callouts, images, videos, attachments, math blocks, toggles, and code blocks
- Add custom table extension with smart Tab key handling for list indentation within tables
- Preserve default table navigation when not in lists

packages/editor-ext/src/lib/table/header.ts

@@ -2,7 +2,7 @@ import { TableHeader as TiptapTableHeader } from "@tiptap/extension-table-header
 
 export const TableHeader = TiptapTableHeader.extend({
   name: "tableHeader",
-  content: "paragraph+",
+  content: "(paragraph | heading | bulletList | orderedList | taskList | blockquote | callout | image | video | attachment | mathBlock | details | codeBlock)+",
   
   addAttributes() {
     return {