Fix circular dependency resolution by switching to artifact-centric display

- Add artifact: prefix handling in resolve_dependencies for direct artifact
  ID references, enabling dependency resolution for tagless artifacts
- Refactor PackagePage from tag-based to artifact-based data display
- Add PackageArtifact type with tags array for artifact-centric API responses
- Update download URLs to use artifact:ID prefix when no tags exist
- Conditionally show "View Ensure File" only when artifact has tags

backend/app/dependencies.py

@@ -680,14 +680,23 @@ def resolve_dependencies(
     if not package:
         raise DependencyNotFoundError(project_name, package_name, ref)
 
-    # Try to find artifact by tag or version
-    resolved = _resolve_dependency_to_artifact(
-        db, project_name, package_name, ref, ref
-    )
-    if not resolved:
-        raise DependencyNotFoundError(project_name, package_name, ref)
-
-    root_artifact_id, root_version, root_size = resolved
+    # Handle artifact: prefix for direct artifact ID references
+    if ref.startswith("artifact:"):
+        artifact_id = ref[9:]
+        artifact = db.query(Artifact).filter(Artifact.id == artifact_id).first()
+        if not artifact:
+            raise DependencyNotFoundError(project_name, package_name, ref)
+        root_artifact_id = artifact.id
+        root_version = artifact_id[:12]  # Use short hash as version display
+        root_size = artifact.size
+    else:
+        # Try to find artifact by tag or version
+        resolved = _resolve_dependency_to_artifact(
+            db, project_name, package_name, ref, ref
+        )
+        if not resolved:
+            raise DependencyNotFoundError(project_name, package_name, ref)
+        root_artifact_id, root_version, root_size = resolved
 
     # Track resolved artifacts and their versions
     resolved_artifacts: Dict[str, ResolvedArtifact] = {}