Fix examples for renamed leaf endpoint surface

Update the remote shell examples to use unshell::leaves and the leaf_endpoint feature-gated endpoint module, and restore the local macro aliasing needed after removing the direct unshell dependency from unshell-leaves.

src/lib.rs

@@ -23,6 +23,9 @@ pub mod logger;
 /// proc-macro output and downstream code do not need a second migration.
 pub use unshell_protocol as protocol;
 
+/// Re-export the leaf library crate behind the historical `unshell::leaves` path
+pub use unshell_leaves as leaves;
+
 pub use unshell_macros::{Leaf, Procedure, procedures};
 
 // pub use ush_obfuscate as obfuscate;