refactor(cli): separate binary entry points from library logic

Move the main execution logic to a dedicated internal module and create distinct entry files for each binary to improve project structure and build configuration.

crates/irtt-cli/src/entry.rs

@@ -0,0 +1,80 @@
+use std::{
+    env,
+    ffi::OsString,
+    process::ExitCode,
+    sync::{atomic::AtomicBool, Arc},
+};
+
+use crate::{
+    applet::{dispatch_from_argv, AppletDispatch, RequestedApplet},
+    signal::install_signal_handler,
+};
+
+pub fn main() -> ExitCode {
+    match run_from_env() {
+        Ok(()) => ExitCode::SUCCESS,
+        Err(err) => {
+            eprintln!("irtt-rs: {err}");
+            ExitCode::FAILURE
+        }
+    }
+}
+
+fn run_from_env() -> Result<(), Box<dyn std::error::Error>> {
+    let argv: Vec<OsString> = env::args_os().collect();
+    let (requested, argv) = match dispatch_from_argv(argv)? {
+        AppletDispatch::Run { applet, argv } => (applet, argv),
+        AppletDispatch::Help(help) => {
+            print!("{help}");
+            return Ok(());
+        }
+    };
+
+    let shutdown_requested = Arc::new(AtomicBool::new(false));
+    install_signal_handler(Arc::clone(&shutdown_requested))
+        .map_err(|err| format!("failed to install signal handler: {err}"))?;
+
+    match requested {
+        RequestedApplet::Client => run_client_applet(argv, shutdown_requested.as_ref()),
+        RequestedApplet::Tui => run_tui_applet(argv, shutdown_requested.as_ref()),
+        RequestedApplet::Server => Err("server applet is not available in this build".into()),
+    }
+}
+
+#[cfg(feature = "client")]
+fn run_client_applet(
+    argv: Vec<OsString>,
+    shutdown_requested: &AtomicBool,
+) -> Result<(), Box<dyn std::error::Error>> {
+    use clap::Parser;
+
+    let args = crate::cmd::client::ClientArgs::parse_from(argv);
+    crate::cmd::client::run_stream(args, shutdown_requested)
+}
+
+#[cfg(not(feature = "client"))]
+fn run_client_applet(
+    _argv: Vec<OsString>,
+    _shutdown_requested: &AtomicBool,
+) -> Result<(), Box<dyn std::error::Error>> {
+    Err("client applet is not available; rebuild with the client feature".into())
+}
+
+#[cfg(feature = "tui")]
+fn run_tui_applet(
+    argv: Vec<OsString>,
+    shutdown_requested: &AtomicBool,
+) -> Result<(), Box<dyn std::error::Error>> {
+    use clap::Parser;
+
+    let args = crate::cmd::tui::TuiArgs::parse_from(argv);
+    crate::cmd::tui::run_tui(args, shutdown_requested)
+}
+
+#[cfg(not(feature = "tui"))]
+fn run_tui_applet(
+    _argv: Vec<OsString>,
+    _shutdown_requested: &AtomicBool,
+) -> Result<(), Box<dyn std::error::Error>> {
+    Err("TUI applet is not available; rebuild with the tui feature".into())
+}