fix(status): align with Composer's StatusCommand pipeline

Replace the dist-hash tree-diff implementation with Composer's VCS-level
status flow: three buckets (errors / unpushed_changes / vcs_version_changes)
populated via ChangeReportInterface / DvcsDownloaderInterface /
VcsCapableDownloaderInterface, and a bitfield exit code (1|2|4) instead
of always 1.

Supporting work:
- mozart-semver: add normalize_branch (VersionParser::normalizeBranch).
- mozart-vcs: extend VcsDownloader trait with unpushed_changes /
  vcs_reference; port GitDownloader::getUnpushedChanges (HEAD-ref
  discovery + git diff --name-status remote...branch + two-pass fetch);
  fix git status invocation to use --untracked-files=no (Composer parity);
  add hasMetadataRepository preconditions to git/hg/svn local_changes;
  port VersionGuesser (git/hg/svn dispatch — Fossil omitted, feature
  branch detection runs sequentially instead of via async promises).
- mozart-core: extend LocalPackage with pretty_version, package_type,
  installation_source, source, dist, extra; add InstallationSource and
  PackageReference. factory.rs reads them from installed.json.
- mozart-registry: new download_manager mirroring
  DownloadManager::getDownloaderForPackage.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

1 files changed, 96 insertions, 4 deletions

diff --git a/crates/mozart-core/src/composer.rs b/crates/mozart-core/src/composer.rs
index 6fe022a..66bae92 100644
--- a/crates/mozart-core/src/composer.rs
+++ b/crates/mozart-core/src/composer.rs
@@ -92,20 +92,72 @@ pub struct Composer {
     locker: Locker,
 }
 
-/// Subset of `Composer\Package\PackageInterface` needed by the
-/// installation manager. Today only the fields referenced by
-/// `LibraryInstaller::getInstallPath` (`prettyName`, `targetDir`).
+/// Which source the package was installed from. Mirrors
+/// `PackageInterface::getInstallationSource` ("source" | "dist").
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum InstallationSource {
+    Source,
+    Dist,
+}
+
+impl InstallationSource {
+    /// Parse the `installation-source` field from `installed.json`.
+    pub fn parse(s: &str) -> Option<Self> {
+        match s {
+            "source" => Some(InstallationSource::Source),
+            "dist" => Some(InstallationSource::Dist),
+            _ => None,
+        }
+    }
+}
+
+/// Source/dist descriptor — mirrors the nested `source`/`dist` objects in
+/// `installed.json`.
+#[derive(Debug, Clone)]
+pub struct PackageReference {
+    pub kind: String,
+    pub url: String,
+    pub reference: Option<String>,
+    pub shasum: Option<String>,
+}
+
+/// Subset of `Composer\Package\PackageInterface` carried through Mozart's
+/// `LocalRepository`. Holds the fields needed by both the installation
+/// manager (`prettyName`, `targetDir`) and the status command
+/// (installation source, source/dist refs, version, extra).
 #[derive(Debug, Clone)]
 pub struct LocalPackage {
     pretty_name: String,
+    pretty_version: String,
     target_dir: Option<String>,
+    package_type: Option<String>,
+    installation_source: Option<InstallationSource>,
+    source: Option<PackageReference>,
+    dist: Option<PackageReference>,
+    extra: serde_json::Value,
 }
 
 impl LocalPackage {
-    pub fn new(pretty_name: String, target_dir: Option<String>) -> Self {
+    #[allow(clippy::too_many_arguments)]
+    pub fn new(
+        pretty_name: String,
+        pretty_version: String,
+        target_dir: Option<String>,
+        package_type: Option<String>,
+        installation_source: Option<InstallationSource>,
+        source: Option<PackageReference>,
+        dist: Option<PackageReference>,
+        extra: serde_json::Value,
+    ) -> Self {
         Self {
             pretty_name,
+            pretty_version,
             target_dir,
+            package_type,
+            installation_source,
+            source,
+            dist,
+            extra,
         }
     }
 
@@ -115,11 +167,51 @@ impl LocalPackage {
         &self.pretty_name
     }
 
+    /// Original-case version string (e.g. `v1.0.0`). Mirrors
+    /// `PackageInterface::getPrettyVersion`.
+    pub fn pretty_version(&self) -> &str {
+        &self.pretty_version
+    }
+
     /// Optional sub-directory inside the install path that holds the
     /// package code. Mirrors `PackageInterface::getTargetDir`.
     pub fn target_dir(&self) -> Option<&str> {
         self.target_dir.as_deref()
     }
+
+    /// Mirrors `PackageInterface::getType`.
+    pub fn package_type(&self) -> Option<&str> {
+        self.package_type.as_deref()
+    }
+
+    /// Mirrors `PackageInterface::getInstallationSource`.
+    pub fn installation_source(&self) -> Option<InstallationSource> {
+        self.installation_source
+    }
+
+    pub fn source(&self) -> Option<&PackageReference> {
+        self.source.as_ref()
+    }
+
+    pub fn dist(&self) -> Option<&PackageReference> {
+        self.dist.as_ref()
+    }
+
+    /// Mirrors `PackageInterface::getSourceReference`.
+    pub fn source_reference(&self) -> Option<&str> {
+        self.source.as_ref().and_then(|r| r.reference.as_deref())
+    }
+
+    /// Mirrors `PackageInterface::getDistReference`.
+    pub fn dist_reference(&self) -> Option<&str> {
+        self.dist.as_ref().and_then(|r| r.reference.as_deref())
+    }
+
+    /// Raw `extra` field — used by VersionGuesser to read
+    /// `branch-alias`, `non-feature-branches`, etc.
+    pub fn extra(&self) -> &serde_json::Value {
+        &self.extra
+    }
 }
 
 /// In-memory mirror of `Composer\Repository\InstalledFilesystemRepository`