fix(global): add ~/.composer fallback, XDG auto-detection, and no-arg handling

Rewrite composer_home() with Composer-compatible resolution: detect XDG
environment (any XDG_* var or /etc/xdg), prefer existing directories,
and fall back to ~/.composer for legacy systems. Consolidate duplicate
composer_home_dir() from global.rs into shared config_helpers. Accept
no subcommand gracefully with a helpful error instead of a parse error.

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

1 files changed, 1 insertions, 1 deletions

diff --git a/crates/mozart/src/commands/repository.rs b/crates/mozart/src/commands/repository.rs
index e9c52f4..f8e151d 100644
--- a/crates/mozart/src/commands/repository.rs
+++ b/crates/mozart/src/commands/repository.rs
@@ -47,7 +47,7 @@ fn resolve_file_path(args: &RepositoryArgs, cli: &super::Cli) -> anyhow::Result<
         anyhow::bail!("Cannot combine --global and --file");
     }
     if args.global {
-        return Ok(PathBuf::from(composer_home()).join("config.json"));
+        return Ok(composer_home().join("config.json"));
     }
     if let Some(ref file) = args.file {
         return Ok(PathBuf::from(file));