chore: update n8n to ^1.104.1 and bump version to 2.8.1

- Updated n8n to ^1.104.1
- Updated n8n-core to ^1.103.1
- Updated n8n-workflow to ^1.101.0
- Updated @n8n/n8n-nodes-langchain to ^1.103.1
- Rebuilt node database with 532 nodes
- Sanitized 499 workflow templates
- All 1,182 tests passing (933 unit, 249 integration)
- All validation tests passing
- Built and prepared for npm publish

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

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

README.md

@@ -2,11 +2,11 @@
 
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
 [![GitHub stars](https://img.shields.io/github/stars/czlonkowski/n8n-mcp?style=social)](https://github.com/czlonkowski/n8n-mcp)
-[![Version](https://img.shields.io/badge/version-2.8.0-blue.svg)](https://github.com/czlonkowski/n8n-mcp)
+[![Version](https://img.shields.io/badge/version-2.8.1-blue.svg)](https://github.com/czlonkowski/n8n-mcp)
 [![npm version](https://img.shields.io/npm/v/n8n-mcp.svg)](https://www.npmjs.com/package/n8n-mcp)
 [![codecov](https://codecov.io/gh/czlonkowski/n8n-mcp/graph/badge.svg?token=YOUR_TOKEN)](https://codecov.io/gh/czlonkowski/n8n-mcp)
 [![Tests](https://img.shields.io/badge/tests-1356%20passing-brightgreen.svg)](https://github.com/czlonkowski/n8n-mcp/actions)
-[![n8n version](https://img.shields.io/badge/n8n-v1.103.2-orange.svg)](https://github.com/n8n-io/n8n)
+[![n8n version](https://img.shields.io/badge/n8n-^1.104.1-orange.svg)](https://github.com/n8n-io/n8n)
 [![Docker](https://img.shields.io/badge/docker-ghcr.io%2Fczlonkowski%2Fn8n--mcp-green.svg)](https://github.com/czlonkowski/n8n-mcp/pkgs/container/n8n-mcp)
 [![Deploy on Railway](https://railway.com/button.svg)](https://railway.com/deploy/VY6UOG?referralCode=n8n-mcp)