cli: add 'completions <SHELL>' subcommand via clap_complete

crates/relicario-cli/src/main.rs

@@ -8,7 +8,8 @@ mod session;
 use std::path::PathBuf;
 
 use anyhow::{bail, Context, Result};
-use clap::{Parser, Subcommand};
+use clap::{CommandFactory, Parser, Subcommand};
+use clap_complete::{generate, Shell};
 
 #[derive(Parser)]
 #[command(
@@ -163,6 +164,13 @@ enum Commands {
 
     /// Lock the vault (no-op in CLI; present for UX parity with the extension).
     Lock,
+
+    /// Emit a shell completion script for the given shell.
+    /// Pipe to your shell's completion file (e.g. `> /etc/bash_completion.d/relicario`).
+    Completions {
+        #[arg(value_enum)]
+        shell: Shell,
+    },
 }
 
 #[derive(Subcommand)]
@@ -354,6 +362,11 @@ fn main() -> Result<()> {
         Commands::Status => cmd_status(),
         Commands::Device { action } => cmd_device(action),
         Commands::Lock => { eprintln!("no cached session to lock"); Ok(()) }
+        Commands::Completions { shell } => {
+            let mut cmd = Cli::command();
+            generate(shell, &mut cmd, "relicario", &mut std::io::stdout());
+            Ok(())
+        }
     }
 }