test(media): cover upload-url acceptance for mp4/m4a audio

tests/test_chat_message_flow.py

@@ -166,6 +166,33 @@ async def test_chat_list_includes_notification_muted_flag(client, db_session):
     assert row["muted"] is True
 
 
+async def test_media_upload_url_accepts_mp4_voice_mime_types(client, db_session):
+    user = await _create_verified_user(
+        client,
+        db_session,
+        "media_mime_user@example.com",
+        "media_mime_user",
+        "strongpass123",
+    )
+    auth = {"Authorization": f"Bearer {user['access_token']}"}
+
+    mp4_response = await client.post(
+        "/api/v1/media/upload-url",
+        headers=auth,
+        json={"file_name": "voice.m4a", "file_type": "audio/mp4", "file_size": 2048},
+    )
+    assert mp4_response.status_code == 200
+    assert "upload_url" in mp4_response.json()
+
+    m4a_response = await client.post(
+        "/api/v1/media/upload-url",
+        headers=auth,
+        json={"file_name": "voice-alt.m4a", "file_type": "audio/x-m4a", "file_size": 2048},
+    )
+    assert m4a_response.status_code == 200
+    assert "upload_url" in m4a_response.json()
+
+
 async def test_private_chat_respects_contacts_only_policy(client, db_session):
     u1 = await _create_verified_user(client, db_session, "pm_u1@example.com", "pm_user_one", "strongpass123")
     u2 = await _create_verified_user(client, db_session, "pm_u2@example.com", "pm_user_two", "strongpass123")