Update README.md to explain Agent mode will start the server

Author: srt32

README.md

@@ -23,7 +23,7 @@ The MCP server can use many of the GitHub APIs, so enable the permissions that y
 
 ### Usage with VS Code
 
-For quick installation, use one of the one-click install buttons at the top of this README.
+For quick installation, use one of the one-click install buttons at the top of this README. Once you complete that flow, toggle Agent mode and the server will start.
 
 For manual installation, add the following JSON block to your User Settings (JSON) file in VS Code. You can do this by pressing `Ctrl + Shift + P` and typing `Preferences: Open User Settings (JSON)`.