refactor media module

apps/api/src/domain/media/presenters/GetMediaPresenter.ts

@@ -14,15 +14,21 @@ export class GetMediaPresenter implements UseCaseOutputPort<GetMediaResult> {
   present(result: GetMediaResult): void {
     const media = result.media;
 
-    this.model = {
+    const model: GetMediaResponseModel = {
       id: media.id,
       url: media.url,
       type: media.type,
-      // Best-effort mapping from arbitrary metadata
-      category: (media.metadata as { category?: string } | undefined)?.category,
       uploadedAt: media.uploadedAt,
       size: media.size,
     };
+
+    // Best-effort mapping from arbitrary metadata
+    const category = (media.metadata as { category?: string } | undefined)?.category;
+    if (category !== undefined) {
+      model.category = category;
+    }
+
+    this.model = model;
   }
 
   getResponseModel(): GetMediaResponseModel | null {

apps/api/src/domain/media/presenters/UploadMediaPresenter.ts

@@ -12,11 +12,16 @@ export class UploadMediaPresenter implements UseCaseOutputPort<UploadMediaResult
   }
 
   present(result: UploadMediaResult): void {
-    this.model = {
+    const model: UploadMediaResponseModel = {
       success: true,
       mediaId: result.mediaId,
-      url: result.url,
     };
+    
+    if (result.url !== undefined) {
+      model.url = result.url;
+    }
+    
+    this.model = model;
   }
 
   getResponseModel(): UploadMediaResponseModel | null {