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>

3 files changed, 26 insertions, 0 deletions

diff --git a/crates/mozart/Cargo.toml b/crates/mozart/Cargo.toml
index e219fff..ccf7f94 100644
--- a/crates/mozart/Cargo.toml
+++ b/crates/mozart/Cargo.toml
@@ -8,6 +8,7 @@ anyhow = "1.0.101"
 bzip2 = "0.5"
 filetime = "0.2"
 clap = { version = "4.5.57", features = ["derive"] }
+clap_complete = "4"
 colored = "3.1.1"
 dialoguer = "0.12.0"
 flate2 = "1"
diff --git a/crates/mozart/src/commands.rs b/crates/mozart/src/commands.rs
index 694b4e1..285f65d 100644
--- a/crates/mozart/src/commands.rs
+++ b/crates/mozart/src/commands.rs
@@ -5,6 +5,7 @@ pub mod browse;
 pub mod bump;
 pub mod check_platform_reqs;
 pub mod clear_cache;
+pub mod completion;
 pub mod config;
 pub mod create_project;
 pub mod dependency;
@@ -105,6 +106,9 @@ pub enum Commands {
     #[command(name = "clear-cache", alias = "clearcache", alias = "cc")]
     ClearCache(clear_cache::ClearCacheArgs),
 
+    /// Generate shell completion scripts
+    Completion(completion::CompletionArgs),
+
     /// Sets config options
     Config(config::ConfigArgs),
 
@@ -203,6 +207,7 @@ pub fn execute(cli: &Cli) -> anyhow::Result<()> {
         Commands::Bump(args) => bump::execute(args, cli, &console),
         Commands::CheckPlatformReqs(args) => check_platform_reqs::execute(args, cli, &console),
         Commands::ClearCache(args) => clear_cache::execute(args, cli, &console),
+        Commands::Completion(args) => completion::execute(args, cli, &console),
         Commands::Config(args) => config::execute(args, cli, &console),
         Commands::CreateProject(args) => create_project::execute(args, cli, &console),
         Commands::Depends(args) => depends::execute(args, cli, &console),
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(())
+}