Add Authorization to key components list in overview

Include Authorization framework in the list of key MCP components
to better reflect its importance in HTTP-based transports.

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

Co-Authored-By: Claude <[email protected]>

Author: dsp-ant

docs/specification/draft/basic/index.mdx

@@ -11,6 +11,7 @@ The Model Context Protocol consists of several key components that work together
 - **Base Protocol**: Core JSON-RPC message types
 - **Lifecycle Management**: Connection initialization, capability negotiation, and
   session control
+- **Authorization**: Authentication and authorization framework for HTTP-based transports
 - **Server Features**: Resources, prompts, and tools exposed by servers
 - **Client Features**: Sampling and root directory lists provided by clients
 - **Utilities**: Cross-cutting concerns like logging and argument completion