refactor(registry): introduce Repository and InstallerExecutor traits

Sets up DI scaffolding for in-process installer E2E tests, mirroring how
Composer's PHPUnit suite swaps Packagist (FactoryMock) and the install
manager (InstallationManagerMock) without touching the network or filesystem.

Additions:
- Repository trait + RepositorySet (Composer's RepositoryInterface analog),
  with PackagistRepository, InlinePackageRepository, VcsRepository impls.
- InstallerExecutor trait (Composer's InstallationManager analog) with
  FilesystemExecutor extracted from install_from_lock.

install_from_lock now delegates per-package install/uninstall verbs to
FilesystemExecutor; console output orchestration stays in the caller so
existing --EXPECT-OUTPUT-shape assertions remain comparable. No behavior
change - all 136 enabled installer fixtures still pass.

Also tightens the installer_fixture\! ignore form to a single token
(installer_fixture\!(name, ignore)) for readability.

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

1 files changed, 63 insertions, 0 deletions

diff --git a/crates/mozart-registry/src/repository/vcs_repo.rs b/crates/mozart-registry/src/repository/vcs_repo.rs
new file mode 100644
index 0000000..fff5f6f
--- /dev/null
+++ b/crates/mozart-registry/src/repository/vcs_repo.rs
@@ -0,0 +1,63 @@
+//! [`Repository`] for VCS-type repositories.
+//!
+//! Wraps [`crate::vcs_bridge::scan_vcs_repositories`] + [`crate::vcs_bridge::vcs_to_packagist_version`].
+//! Scanning is expensive (clones / fetches), so we do it once at construction
+//! and serve subsequent queries from the in-memory cache. Mirrors
+//! `Composer\Repository\Vcs\VcsRepository`'s lazy-then-memoized behavior.
+
+use super::{LoadResult, NamedPackagistVersion, PackageQuery, Repository};
+use crate::packagist::PackagistVersion;
+use crate::vcs_bridge::{scan_vcs_repositories, vcs_to_packagist_version};
+use mozart_core::package::RawRepository;
+
+pub struct VcsRepository {
+    id: String,
+    versions: Vec<(String, PackagistVersion)>,
+}
+
+impl VcsRepository {
+    /// Scan every VCS-type entry in `repositories` and cache the resulting
+    /// versions. Non-VCS entries are ignored. This performs network I/O.
+    pub async fn from_repositories(repositories: &[RawRepository]) -> Self {
+        let scanned = scan_vcs_repositories(repositories).await;
+        let versions = scanned
+            .iter()
+            .map(|v| (v.name.clone(), vcs_to_packagist_version(v)))
+            .collect();
+        Self {
+            id: "vcs".to_string(),
+            versions,
+        }
+    }
+
+    pub fn version_count(&self) -> usize {
+        self.versions.len()
+    }
+}
+
+#[async_trait::async_trait]
+impl Repository for VcsRepository {
+    fn id(&self) -> &str {
+        &self.id
+    }
+
+    async fn load_packages(&self, queries: &[PackageQuery<'_>]) -> anyhow::Result<LoadResult> {
+        let mut result = LoadResult::default();
+        for query in queries {
+            let mut found_any = false;
+            for (name, version) in &self.versions {
+                if name == query.name {
+                    found_any = true;
+                    result.packages.push(NamedPackagistVersion {
+                        name: name.clone(),
+                        version: version.clone(),
+                    });
+                }
+            }
+            if found_any {
+                result.names_found.push(query.name.to_string());
+            }
+        }
+        Ok(result)
+    }
+}