Switch to Sustainable Use License (fair-code model)

- Replace ISC license with Sustainable Use License v1.0
- Add LICENSE_FAQ.md explaining the fair-code approach
- Update package.json with new license identifier
- Add license headers to main entry point files
- Update README with clear license usage guidelines

Following n8n's licensing approach, this provides:
- Free use for internal business purposes
- Free use for personal/non-commercial projects
- Restrictions on hosting as a service
- Protection against commercial exploitation

No .ee. mechanism implemented yet - all features remain
freely available under the single license.

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

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

src/index-http.ts

@@ -1,4 +1,12 @@
 #!/usr/bin/env node
+/**
+ * n8n Documentation MCP Server
+ * Copyright (c) 2025 n8n-mcp contributors
+ * 
+ * This software is licensed under the Sustainable Use License.
+ * See the LICENSE file in the root directory of this source tree.
+ */
+
 import dotenv from 'dotenv';
 import { N8NDocumentationRemoteServer } from './mcp/remote-server';
 import { logger } from './utils/logger';

src/index-v2.ts

@@ -1,3 +1,12 @@
+#!/usr/bin/env node
+/**
+ * n8n Documentation MCP Server
+ * Copyright (c) 2025 n8n-mcp contributors
+ * 
+ * This software is licensed under the Sustainable Use License.
+ * See the LICENSE file in the root directory of this source tree.
+ */
+
 import dotenv from 'dotenv';
 import { N8NDocumentationMCPServer } from './mcp/server-v2';
 import { MCPServerConfig } from './types';