refactor(composer): move Composer and Factory from mozart-core to mozart

Composer needs DownloadManager (from mozart-registry), but mozart-core
sits below mozart-registry in the dependency graph — adding the field
would create a dependency cycle. Moving Composer and create_composer to
the mozart CLI crate breaks the cycle and lets the root state container
hold a DownloadManager.

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

1 files changed, 9 insertions, 6 deletions

diff --git a/crates/mozart-registry/src/download_manager.rs b/crates/mozart-registry/src/download_manager.rs
index 3e05517..7c6ff73 100644
--- a/crates/mozart-registry/src/download_manager.rs
+++ b/crates/mozart-registry/src/download_manager.rs
@@ -35,7 +35,10 @@ impl DownloadManager {
         Self { git_cache_dir }
     }
 
-    pub fn for_package(&self, package: &LocalPackage) -> Option<Box<dyn VcsDownloader>> {
+    pub fn get_downloader_for_package(
+        &self,
+        package: &LocalPackage,
+    ) -> Option<Box<dyn VcsDownloader>> {
         if package.package_type() == Some("metapackage") {
             return None;
         }
@@ -107,34 +110,34 @@ mod tests {
             None,
             Value::Null,
         );
-        assert!(dm.for_package(&p).is_none());
+        assert!(dm.get_downloader_for_package(&p).is_none());
     }
 
     #[test]
     fn dist_install_returns_none() {
         let dm = DownloadManager::new(PathBuf::from("/tmp/mz-test-cache"));
         let p = pkg(Some(InstallationSource::Dist), Some("git"));
-        assert!(dm.for_package(&p).is_none());
+        assert!(dm.get_downloader_for_package(&p).is_none());
     }
 
     #[test]
     fn source_install_with_git_returns_some() {
         let dm = DownloadManager::new(PathBuf::from("/tmp/mz-test-cache"));
         let p = pkg(Some(InstallationSource::Source), Some("git"));
-        assert!(dm.for_package(&p).is_some());
+        assert!(dm.get_downloader_for_package(&p).is_some());
     }
 
     #[test]
     fn unknown_source_kind_returns_none() {
         let dm = DownloadManager::new(PathBuf::from("/tmp/mz-test-cache"));
         let p = pkg(Some(InstallationSource::Source), Some("perforce"));
-        assert!(dm.for_package(&p).is_none());
+        assert!(dm.get_downloader_for_package(&p).is_none());
     }
 
     #[test]
     fn missing_installation_source_returns_none() {
         let dm = DownloadManager::new(PathBuf::from("/tmp/mz-test-cache"));
         let p = pkg(None, Some("git"));
-        assert!(dm.for_package(&p).is_none());
+        assert!(dm.get_downloader_for_package(&p).is_none());
     }
 }