fix: Add default sort value to create_collection

Collections without sort field cause frontend error:
"Cannot read properties of null (reading 'field')"

Now sets {"field": "index", "direction": "asc"} as default.

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

package.json

@@ -1,6 +1,6 @@
 {
   "name": "mcp-outline-postgresql",
-  "version": "1.3.7",
+  "version": "1.3.8",
   "description": "MCP Server for Outline Wiki via PostgreSQL direct access",
   "main": "dist/index.js",
   "scripts": {