feat: SSE (Server-Sent Events) support for n8n integration

- Added SSE server implementation for real-time event streaming
- Created n8n compatibility mode with strict schema validation
- Implemented session management for concurrent connections
- Added comprehensive SSE documentation and examples
- Enhanced MCP tools with async execution support
- Added Docker Compose configuration for SSE deployment
- Included test scripts and integration tests

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

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

.env.example

@@ -59,6 +59,15 @@ AUTH_TOKEN=your-secure-token-here
 # Default: 0 (disabled)
 # TRUST_PROXY=0
 
+# =========================
+# N8N COMPATIBILITY MODE
+# =========================
+# Enable strict schema compatibility for n8n's MCP Client Tool
+# This mode adds additionalProperties: false to all tool schemas
+# to work around n8n's LangChain schema validation
+# Default: false (standard mode)
+# N8N_COMPATIBILITY_MODE=false
+
 # =========================
 # N8N API CONFIGURATION
 # =========================