Fix PackageArtifactResponse missing sha256 and version fields

- Add sha256 field to list_package_artifacts response (artifact ID is SHA256)
- Add version field to PackageArtifactResponse schema
- Add version field to frontend PackageArtifact type
- Update getArtifactVersion to prefer direct version field

frontend/src/pages/PackagePage.tsx

@@ -313,9 +313,9 @@ function PackagePage() {
     }
   };
 
-  // Helper to get version from artifact metadata
+  // Helper to get version from artifact - prefer direct version field, fallback to metadata
   const getArtifactVersion = (a: PackageArtifact): string | null => {
-    return (a.format_metadata?.version as string) || null;
+    return a.version || (a.format_metadata?.version as string) || null;
   };
 
   // Helper to get download ref - prefer version, fallback to artifact ID

frontend/src/types.ts

@@ -58,6 +58,7 @@ export interface PackageArtifact {
   created_at: string;
   created_by: string;
   format_metadata?: Record<string, unknown> | null;
+  version?: string | null;  // Version from PackageVersion if exists
 }
 
 export interface PackageVersion {