fix: remove faulty auto-generated examples from MCP tools

- Remove examples from get_node_essentials responses
- Remove examples from validate_node_operation when errors occur
- Update documentation to reflect removal of examples
- Keep helpful format hints in get_node_for_task (different purpose)

The auto-generated examples were misleading AI agents with incorrect
configurations (e.g., Slack "channel" vs "select" property). Tools
now focus on validation and error messages instead of examples.

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

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

package.json

@@ -1,6 +1,6 @@
 {
   "name": "n8n-mcp",
-  "version": "2.7.16",
+  "version": "2.7.17",
   "description": "Integration between n8n workflow automation and Model Context Protocol (MCP)",
   "main": "dist/index.js",
   "bin": {