test: update tests for v2.28.5 behavior changes (v2.28.6) (#470)

- Update n8n-version tests: 'v' prefix now supported in version strings
- Update n8n-validation tests: empty settings now return minimal defaults
  { executionOrder: 'v1' } instead of {} to avoid API rejection (Issue #431)

Conceived by Romuald Członkowski - https://www.aiadvisors.pl/en

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Romuald Członkowski <romualdczlonkowski@MacBook-Pro-Romuald.local>
Co-authored-by: Claude <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "n8n-mcp",
-  "version": "2.28.5",
+  "version": "2.28.6",
   "description": "Integration between n8n workflow automation and Model Context Protocol (MCP)",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",