Add compile-time leaf declarations

Introduce a function-like leaf declaration macro, bind endpoint and TUI hosts to shared generated metadata, and move remote shell endpoint construction out of the leaf module into the examples and runtime assembly code.

examples/protocol/remote_shell_receive.rs

@@ -9,7 +9,9 @@ use std::net::TcpListener;
 use unshell::leaves::remote_shell;
 use unshell::leaves::remote_shell::OpenRequest;
 use unshell::protocol::tree::encode_call_reply;
-use unshell::protocol::tree::{Endpoint, EndpointOutcome, Ingress, LocalEvent};
+use unshell::protocol::tree::{
+    ChildRoute, Endpoint, EndpointOutcome, Ingress, LocalEvent, ProtocolEndpoint,
+};
 
 fn main() -> Result<(), Box<dyn Error>> {
     let listener = TcpListener::bind(remote_shell::endpoint::LISTEN_ADDR)?;
@@ -19,10 +21,15 @@ fn main() -> Result<(), Box<dyn Error>> {
     println!("accepted endpoint connection from {peer_addr}");
 
     let frame_rx = remote_shell::endpoint::spawn_frame_reader(stream.try_clone()?);
-    let mut endpoint = remote_shell::endpoint::build_controller_endpoint();
+    let mut endpoint = ProtocolEndpoint::new(
+        Vec::new(),
+        None,
+        vec![ChildRoute::registered(agent_path())],
+        Vec::new(),
+    );
     let hook_id = endpoint.allocate_hook_id();
     let shell_leaf_name = remote_shell::endpoint::RemoteShellEndpoint::protocol_leaf_name();
-    let open_procedure = remote_shell::endpoint::ProcedureOpen::protocol_procedure_id();
+    let open_procedure = remote_shell::endpoint::Open::protocol_procedure_id();
 
     remote_shell::endpoint::send_forward(
         &mut stream,