fix: add version option

src/main.rs

@@ -7,7 +7,7 @@ mod tui;
 use std::path::{Path, PathBuf};
 
 use anyhow::{Context, Error, Result, bail};
-use clap::{Parser, Subcommand};
+use clap::{ArgAction, Parser, Subcommand};
 use config::{Config, LauncherEntry, load_config};
 use detect::detect_beamline;
 
@@ -19,8 +19,12 @@ const LOCAL_CONFIG: &str = "data/defaults.json";
 const DEFAULT_ENV_FILE: &str = "/etc/aaredaq/aaredaq.env";
 
 #[derive(Parser)]
-#[command(name = "aarel")]
+#[command(name = "aarel", version, disable_version_flag = true)]
 struct Cli {
+    /// Print version information.
+    #[arg(short = 'v', long = "version", action = ArgAction::Version)]
+    version: Option<bool>,
+
     /// Path to the launcher config file. Defaults to /etc/aarel/defaults.json,
     /// falling back to ./data/defaults.json.
     #[arg(long)]