Add new harmony_cli sub-crate

harmony_cli/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "harmony_cli"
+edition = "2024"
+version.workspace = true
+readme.workspace = true
+license.workspace = true
+
+[dependencies]
+clap = "4.5.35"

harmony_cli/src/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}