feat: Add Markdown to ProseMirror converter

- New converter supports headings, lists, blockquotes, code blocks
- Documents now render with proper formatting in Outline
- Auto-update collection documentStructure on document creation
- Documents appear in sidebar automatically

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "mcp-outline-postgresql",
-  "version": "1.3.13",
+  "version": "1.3.14",
   "description": "MCP Server for Outline Wiki via PostgreSQL direct access",
   "main": "dist/index.js",
   "scripts": {