Fix TypeScript error: iterate over loader Map values, not entries

The previous fix had a type error because it was iterating over the Map
directly (which yields entries as tuples) instead of using .values() to
iterate over just the MetadataLoader instances.

packages/metadata/src/metadata-manager.ts:166

Co-authored-by: hotlong <50353452+hotlong@users.noreply.github.com>

Author: Claude

packages/metadata/src/metadata-manager.ts

@@ -162,7 +162,7 @@ export class MetadataManager implements IMetadataService {
     this.registry.get(type)!.set(name, data);
 
     // Persist to writable loaders (e.g., DatabaseLoader for history tracking)
-    for (const loader of this.loaders) {
+    for (const loader of this.loaders.values()) {
       if (loader.save) {
         try {
           await loader.save(type, name, data);