refactor(registry): route Packagist queries through RepositorySet

Replace direct packagist::fetch_package_versions calls in
resolver::resolve (seed + transitive loops) and lockfile::generate_lock_file
with repo_set.load_packages calls. PackagistRepository now propagates
errors instead of swallowing them, so the seed loop's strictness and the
transitive loop's local-leniency are both preserved exactly.

VCS and inline-package repositories are still preloaded directly into
the pool builder for now, with their names tracked in skip lists so we
don't double-load them through the trait. Migrating them through
RepositorySet is a follow-up - vcs_to_pool_inputs and
packagist_to_pool_inputs differ in dev-branch handling that needs to be
unified first.

All 136 enabled installer fixtures + 114 mozart-registry tests + 541
mozart lib tests remain green; clippy clean.

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

1 files changed, 12 insertions, 12 deletions

diff --git a/crates/mozart-registry/src/repository/packagist_repo.rs b/crates/mozart-registry/src/repository/packagist_repo.rs
index 17208c1..a3bbf40 100644
--- a/crates/mozart-registry/src/repository/packagist_repo.rs
+++ b/crates/mozart-registry/src/repository/packagist_repo.rs
@@ -32,19 +32,19 @@ impl Repository for PackagistRepository {
     async fn load_packages(&self, queries: &[PackageQuery<'_>]) -> anyhow::Result<LoadResult> {
         let mut result = LoadResult::default();
         for query in queries {
-            // Mirror the existing transitive-loop tolerance: a 404 / network
-            // failure for one name is not fatal — it just means this repo
-            // contributes nothing for that name. `RepositorySet` falls
-            // through, and the solver fails later if no repo knows it.
+            // Errors propagate to the caller. Composer's
+            // `ComposerRepository::loadAsyncPackages` distinguishes 404
+            // (empty result, no error) from transport failures (exception);
+            // Mozart's underlying `fetch_package_versions` doesn't yet make
+            // that distinction, so for now both surface as `Err` and the
+            // caller decides whether the loop wants to continue (transitive
+            // exploration) or abort (seed-time fetch failure).
             let versions =
-                match packagist::fetch_package_versions(query.name, &self.cache).await {
-                    Ok(v) => v,
-                    Err(_) => continue,
-                };
-            // `fetch_package_versions` returning Ok counts as "this repo
-            // authoritatively knows the name", even if the version list is
-            // empty (matches Composer `ArrayRepository::loadPackages` which
-            // adds the name to `namesFound` regardless of constraint match).
+                packagist::fetch_package_versions(query.name, &self.cache).await?;
+            // A successful fetch counts as "this repo authoritatively knows
+            // the name", even if the version list is empty — mirrors
+            // Composer's `ArrayRepository::loadPackages` which adds the
+            // name to `namesFound` regardless of constraint match.
             result.names_found.push(query.name.to_string());
             for version in versions {
                 result.packages.push(NamedPackagistVersion {