Add one resource or one prompt to the servers #276

Problem

Every server exposes only tools, so the quickstart suggests that MCP is just a tool-calling protocol. Adding one resource (for example weather://states, listing the valid state codes) or one prompt (for example "weekend forecast for {city}") would show one of the other two MCP primitives with very little code.

This is the biggest change in scope among these issues, and it changes what the tutorials teach. Maintainers should agree on it before anyone starts work.

Tasks

• Agree with maintainers on which primitive to add and exactly what it looks like.
• Implement it the same way in all five servers, and advertise the matching capability.
• Update the clients:
  • For a resource: list it and read it once when connecting.
  • For a prompt: offer it as a slash command in the chat loop.
• Update all ten READMEs and the links between the tutorials and this repo.
• Extend the test client to list the new primitive.

Out of scope

These are too big for a quickstart; each would roughly double its size:

• sampling
• elicitation
• progress notifications
• cancellation
• the logging capability
• Streamable HTTP transport

For HTTP, the root README already points users to SECURITY.md.

Acceptance criteria

• All five servers expose the agreed resource or prompt and advertise the matching capability.
• All five clients use it as agreed, and the test client lists it.