Improve the documentation

The README.md file must explain how to use the library.
- Explain more what this library provides, in which ways it can be used.
- Use Clojure snippets inside the markdown doc.
- Choose better examples, replace the talk-like-a-pirate prompt with something closer to realworld usage.

Start by reading README.md and compare its current explanation and examples with the library's purpose as a Clojure/ClojureScript MCP client and server toolkit. Update the README to explain what the library provides, show usage with Clojure snippets, and replace the talk-like-a-pirate prompt with a more realistic example; the README should make these uses understandable to readers.

Written by the indexing model from the issue text.