Improve codex remote-control CLI UX (#22878)

## Description

This PR makes `codex remote-control` behave like a foreground CLI
command by default. Running it now starts remote control, waits for
readiness, prints a clear status message with the machine name, and
stays alive until Ctrl-C.

Users who want daemon behavior can use `codex remote-control start`, and
`codex remote-control stop` now prints concise human-readable output.
`--json` remains available for scripts.

Implementation-wise, this now verifies the real app-server state instead
of just assuming startup worked. The CLI starts or connects to
app-server, probes its control socket, calls the `remoteControl/enable`
API, and waits for the remote-control status response/notification
before printing success.

For daemon mode, `codex remote-control start` also reports which managed
app-server binary was used, including its path and best-effort `codex
--version`, so failures are easier to diagnose.

## Examples

Example output:
```
> codex remote-control
Starting app-server with remote control enabled...
This machine is available for remote control as com-97826.
Press Ctrl-C to stop.
```

Error case using daemon (currently expected based on our publicly
released CLI version):
```
> ./target/debug/codex remote-control start
Starting app-server daemon with remote control enabled...
Error: app server did not become ready on /Users/owen/.codex/app-server-control/app-server-control.sock

Daemon used app-server:
  path: /Users/owen/.codex/packages/standalone/current/codex
  version: 0.130.0

Managed app-server stderr (/Users/owen/.codex/app-server-daemon/app-server.stderr.log):
  error: unexpected argument '--remote-control' found
  
  Usage: codex app-server [OPTIONS] [COMMAND]
  
  For more information, try '--help'.

Caused by:
    0: failed to connect to /Users/owen/.codex/app-server-control/app-server-control.sock
    1: No such file or directory (os error 2)
```

## What changed

- `codex remote-control` now runs remote control in the foreground and
prints a Ctrl-C stop hint.
- `codex remote-control start` starts the daemon and waits for remote
control readiness before reporting success.
- `codex remote-control stop` reports stopped/not-running status in
plain language.
- Startup failures now include recent managed app-server stderr to make
daemon issues easier to diagnose.
- Added coverage for CLI output, readiness waiting, foreground shutdown,
and stderr log tailing.

codex-rs/app-server/src/lib.rs

@@ -400,6 +400,7 @@ pub enum PluginStartupTasks {
 pub struct AppServerRuntimeOptions {
     pub plugin_startup_tasks: PluginStartupTasks,
     pub remote_control_enabled: bool,
+    pub install_shutdown_signal_handler: bool,
 }
 
 impl Default for AppServerRuntimeOptions {
@@ -407,6 +408,7 @@ impl Default for AppServerRuntimeOptions {
         Self {
             plugin_startup_tasks: PluginStartupTasks::Start,
             remote_control_enabled: false,
+            install_shutdown_signal_handler: true,
         }
     }
 }
@@ -645,7 +647,8 @@ pub async fn run_main_with_transport_options(
 
     let single_client_mode = matches!(&transport, AppServerTransport::Stdio);
     let shutdown_when_no_connections = single_client_mode;
-    let graceful_signal_restart_enabled = !single_client_mode;
+    let graceful_signal_restart_enabled =
+        runtime_options.install_shutdown_signal_handler && !single_client_mode;
     let mut app_server_client_name_rx = None;
 
     match &transport {