fix: hide outbound media from gallery

tests/web/media-route.test.ts

@@ -20,6 +20,39 @@ afterEach(async () => {
 });
 
 describe('media route username presentation', () => {
+  it('lists received media while excluding items sent by the owning account', async () => {
+    const mediaItem = (id: string, sender: string) => ({
+      accountId: 't2_owner', id, chatUsername: 'alice', chatRoomId: 'room-one', sender,
+      timestamp: 1, originalUrl: `mxc://${id}`, fileName: `${id}.jpg`, relativePath: `${id}.jpg`, createdAt: 2,
+    });
+    const context = {
+      logger: { error: vi.fn() },
+      services: {
+        media: { getMediaItems: vi.fn().mockResolvedValue([
+          mediaItem('received', 'alice'),
+          mediaItem('sent-marker', 'Me'),
+          mediaItem('sent-matrix-id', '@t2_owner:reddit.com'),
+          mediaItem('sent-username', 'owner'),
+        ]) },
+        chat: {
+          getCachedConversations: vi.fn().mockResolvedValue([]),
+          resolveSenderDisplay: vi.fn((identity: string) => identity),
+        },
+        redditAccounts: {
+          get: vi.fn().mockReturnValue({ accountId: 't2_owner', redditUsername: 'owner' }),
+        },
+      },
+    } as unknown as WebContext;
+    const app = express().use('/api', createMediaRouter(context));
+
+    const response = await request(app, '/api/media');
+
+    expect(response.status).toBe(200);
+    expect(await response.json()).toEqual([
+      expect.objectContaining({ id: 'received', sender: 'alice' }),
+    ]);
+  });
+
   it('upgrades historical t2 fields through the chat username map', async () => {
     const context = {
       logger: { error: vi.fn() },