Initial implementation of n8n MCP server

Implements Hybrid MCP Light pattern with:
- 5 curated tools: list_workflows, get_workflow, list_executions, get_execution, trigger_webhook
- API pass-through tool: n8n_api_call for complete coverage
- API reference resource: n8n://api-reference
- Dockerfile and CI workflow for Gitea container registry

.env.example

@@ -0,0 +1,11 @@
+# n8n MCP Server Configuration
+# Copy this file to .env and fill in your values
+
+# n8n Instance URL (without trailing slash)
+N8N_URL=https://n8n.example.com
+
+# n8n API Key (generate from n8n Settings > API)
+N8N_API_KEY=your-api-key-here
+
+# Optional: Server port (default: 8000)
+# PORT=8000