Keep MCP's chat demo notes in its own skill, so the shared skills match #91

The chat demo added a paragraph each to MCP's shared docker-and-compose and template-authoring skills, so they no longer match the other four templates, and Monday's drift check will flag them.

• Move both notes into MCP's mcp-inspector skill and take them out of the shared skills (Keep MCP's chat demo notes in its own skill CleanModelContextProtocol#63)
• Shared Layers Drift is green when run by hand