Fix design file metadata mapping in files store

Co-Authored-By: Codex <codex@openai.com>

tests/stores/files.test.js

@@ -105,6 +105,33 @@ describe('filesStore', () => {
       mockGet.mockRejectedValue(new Error('Network error'));
       await expect(store.fetchAllFiles()).resolves.toBeUndefined();
     });
+
+    it('maps design files without leaking metadata from previous file items', async () => {
+      mockGet.mockResolvedValue({
+        data: [
+          {
+            type: 'log',
+            name: 'order-log',
+            owner: { name: 'Alice' },
+            updated_at: '2024-01-15T10:00:00Z',
+            accessed_at: null,
+          },
+          {
+            type: 'design',
+            name: 'diagram-a',
+            owner: { name: 'Bob' },
+            updated_at: '2024-01-16T10:00:00Z',
+            accessed_at: null,
+          },
+        ],
+      });
+
+      await store.fetchAllFiles();
+
+      expect(store.allEventFiles[1].icon).toBe('shape_line');
+      expect(store.allEventFiles[1].fileType).toBe('Design');
+      expect(store.allEventFiles[1].parentLog).toBe('diagram-a');
+    });
   });
 
   describe('upload', () => {