feat(resolver): add branch-alias support across the resolution pipeline

Plumb Composer's `extra.branch-alias` mechanism end-to-end so a dev
branch (e.g. `dev-foobar`) can be installed alongside its numeric alias
(e.g. `3.2.x-dev`) and resolve constraints written against the alias
target.

Concretely:
- `mozart-semver`: stop treating pure-numeric `-dev` as a wildcard
  branch — `3.2.9999999.9999999-dev` (the form `normalizeBranch` emits)
  now parses as a classical version with `is_dev_branch=false`, so
  constraints like `3.2.*` match it.
- `mozart-registry/composer_repo`: load `type: composer` repositories
  from `file://` URLs (legacy embedded `packages.json`).
- `mozart-registry/resolver`: emit pool entries in pairs for dev
  branches with `extra.branch-alias`, link them via `is_alias_of`, and
  apply `@dev`/`@beta` etc. stability suffix flags from root requires.
- `mozart-sat-resolver`: alias rules (`PackageAlias` /
  `PackageInverseAlias`) so alias and target install together; alias
  packages skipped from same-name conflict indexing.
- `mozart-sat-resolver/policy`: `DefaultPolicy` now honors
  `prefer_stable` via Composer's stability-tier comparison.
- `mozart-registry/lockfile`: split resolved set into real packages vs.
  alias entries; populate the `aliases[]` block.
- `mozart-registry/installer_executor`: new `MarkAliasInstalled`
  operation; `format_full_pretty_version` mirroring
  `BasePackage::getFullPrettyVersion` (appends source ref[0..7] for
  dev/git packages).
- Test harness rewrites fixture-relative `file://` URLs to absolute
  paths.

Newly green fixtures: `install_branch_alias_composer_repo`,
`alias_solver_problems`, `alias_solver_problems2`,
`conflict_with_all_dependencies_option_dont_recommend_to_use_it`,
`unbounded_conflict_does_not_match_default_branch_with_branch_alias`,
`unbounded_conflict_does_not_match_default_branch_with_numeric_branch`.

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

1 files changed, 60 insertions, 3 deletions

diff --git a/crates/mozart-registry/src/installer_executor/mod.rs b/crates/mozart-registry/src/installer_executor/mod.rs
index c70fe12..ff3d7a8 100644
--- a/crates/mozart-registry/src/installer_executor/mod.rs
+++ b/crates/mozart-registry/src/installer_executor/mod.rs
@@ -15,7 +15,7 @@
 
 use std::path::PathBuf;
 
-use crate::lockfile::LockedPackage;
+use crate::lockfile::{LockAlias, LockedPackage};
 
 pub mod filesystem;
 pub mod trace_recorder;
@@ -35,18 +35,75 @@ pub enum PackageOperation<'a> {
         from_version: &'a str,
         package: &'a LockedPackage,
     },
+    /// Mark an alias of a real package as installed. No filesystem effects —
+    /// only the trace recorder needs this. Mirrors Composer's
+    /// `MarkAliasInstalledOperation`.
+    MarkAliasInstalled {
+        /// The alias entry from `composer.lock`'s `aliases[]` block. Carries
+        /// pretty + normalized alias version and the target's pretty version.
+        alias: &'a LockAlias,
+        /// The target package the alias points at — used to source the
+        /// reference suffix for the trace line.
+        target: &'a LockedPackage,
+    },
 }
 
 impl<'a> PackageOperation<'a> {
-    pub fn package(&self) -> &'a LockedPackage {
+    pub fn package(&self) -> Option<&'a LockedPackage> {
         match self {
             PackageOperation::Install { package } | PackageOperation::Update { package, .. } => {
-                package
+                Some(package)
             }
+            PackageOperation::MarkAliasInstalled { .. } => None,
         }
     }
 }
 
+/// Mirror Composer's `BasePackage::getFullPrettyVersion()` for a `LockedPackage`.
+///
+/// For dev-stability versions backed by a git/hg source, append the reference
+/// (truncated to 7 chars when it looks like a 40-char sha1). Otherwise return
+/// the pretty version unchanged.
+pub fn format_full_pretty_version(pkg: &LockedPackage) -> String {
+    format_full_pretty_with_pretty(&pkg.version, pkg)
+}
+
+/// Same as [`format_full_pretty_version`] but lets the caller supply an
+/// alternate pretty version (used by `MarkAliasInstalled` so the alias's
+/// `3.2.x-dev` text is rendered with the *target's* reference).
+pub fn format_full_pretty_with_pretty(pretty_version: &str, pkg: &LockedPackage) -> String {
+    let is_dev = mozart_semver::Version::parse(&pkg.version)
+        .map(|v| matches!(v.pre_release.as_deref(), Some("dev")) || v.is_dev_branch)
+        .unwrap_or(false);
+    if !is_dev {
+        return pretty_version.to_string();
+    }
+    let source_ref = pkg.source.as_ref().and_then(|s| s.reference.as_deref());
+    let dist_ref = pkg.dist.as_ref().and_then(|d| d.reference.as_deref());
+    let source_type = pkg.source.as_ref().map(|s| s.source_type.as_str());
+    // Composer falls back to dist reference only when no source type is set
+    // (or the package isn't git/hg — in which case the dev display is skipped
+    // entirely above).
+    let reference = source_ref.or(match source_type {
+        Some("git") | Some("hg") => None,
+        _ => dist_ref,
+    });
+    let Some(reference) = reference else {
+        return pretty_version.to_string();
+    };
+    if matches!(source_type, Some("git") | Some("hg")) && reference.len() == 40 {
+        format!("{} {}", pretty_version, &reference[..7])
+    } else if matches!(source_type, Some("svn")) {
+        // svn references are revision numbers, never truncated
+        format!("{} {}", pretty_version, reference)
+    } else if reference.len() == 40 {
+        // dist-ref fallback (no git/hg source) — Composer truncates here too
+        format!("{} {}", pretty_version, &reference[..7])
+    } else {
+        format!("{} {}", pretty_version, reference)
+    }
+}
+
 /// Per-call configuration shared across executor methods. Owned by the
 /// caller (typically `install_from_lock`) so the executor sees a consistent
 /// view across an entire install/update run.