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>

2 files changed, 17 insertions, 0 deletions

diff --git a/crates/mozart/src/commands/install.rs b/crates/mozart/src/commands/install.rs
index 356d622..9555ba7 100644
--- a/crates/mozart/src/commands/install.rs
+++ b/crates/mozart/src/commands/install.rs
@@ -670,6 +670,22 @@ pub async fn install_from_lock(
                 }
             };
             executor.install_package(op, &exec_ctx).await?;
+
+            // After the target install/update, emit MarkAliasInstalled for any
+            // aliases whose `package`+`version` (the target's pretty version)
+            // match. Mirrors Composer's `Transaction::calculateOperations` DFS
+            // which pushes alias targets first and emits MarkAliasInstalled
+            // when the alias itself is processed.
+            for alias in &lock.aliases {
+                if alias.package.eq_ignore_ascii_case(&pkg.name) && alias.version == pkg.version {
+                    executor
+                        .install_package(
+                            PackageOperation::MarkAliasInstalled { alias, target: pkg },
+                            &exec_ctx,
+                        )
+                        .await?;
+                }
+            }
         }
 
         // Step 8: Write updated vendor/composer/installed.json (unless download_only)
diff --git a/crates/mozart/src/commands/update.rs b/crates/mozart/src/commands/update.rs
index 9ac2664..847ccf7 100644
--- a/crates/mozart/src/commands/update.rs
+++ b/crates/mozart/src/commands/update.rs
@@ -1370,6 +1370,7 @@ mod tests {
             version: version.to_string(),
             version_normalized: format!("{}.0", version),
             is_dev: false,
+            alias_of_normalized: None,
         }
     }