docs: add a simple chat client for example (#119)

1. optimize the readme in root
2. add example

Signed-off-by: jokemanfire <hu.dingyang@zte.com.cn>

examples/simple-chat-client/Cargo.toml

@@ -0,0 +1,20 @@
+[package]
+name = "simple-chat-client"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+tokio = { version = "1", features = ["full"] }
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"
+reqwest = { version = "0.11", features = ["json"] }
+anyhow = "1.0"
+thiserror = "1.0"
+async-trait = "0.1"
+futures = "0.3"
+toml = "0.8"
+rmcp = { git = "https://github.com/modelcontextprotocol/rust-sdk", features = [
+    "client",
+    "transport-child-process",
+    "transport-sse",
+], no-default-features = true }