feat(completion): add shell completion generation via clap_complete

Add a `completion` subcommand that generates shell completion scripts
for Bash, Zsh, Fish, Elvish, and PowerShell using the clap_complete
crate.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/crates/mozart/src/commands/completion.rs b/crates/mozart/src/commands/completion.rs
new file mode 100644
index 0000000..406749c
--- /dev/null
+++ b/crates/mozart/src/commands/completion.rs
@@ -0,0 +1,20 @@
+use clap::Args;
+use clap::CommandFactory;
+use clap_complete::aot::Shell;
+
+#[derive(Args)]
+pub struct CompletionArgs {
+    /// The shell to generate completions for
+    #[arg(value_enum)]
+    pub shell: Shell,
+}
+
+pub fn execute(
+    args: &CompletionArgs,
+    _cli: &super::Cli,
+    _console: &crate::console::Console,
+) -> anyhow::Result<()> {
+    let mut cmd = super::Cli::command();
+    clap_complete::aot::generate(args.shell, &mut cmd, "mozart", &mut std::io::stdout());
+    Ok(())
+}