Remove context_id support as this is currently being discussed

Author: pwwpche

src/a2a/server/tasks/task_manager.py

@@ -130,8 +130,6 @@ async def save_task_event(
                     task.history = [task.status.message]
                 else:
                     task.history.append(task.status.message)
-            if event.contextId:
-                task.contextId = event.contextId
             if event.metadata:
                 if not task.metadata:
                     task.metadata = {}

tests/server/tasks/test_task_manager.py

@@ -128,18 +128,17 @@ async def test_save_task_event_artifact_update(
     mock_task_store.save.assert_called_once_with(updated_task)
 
 @pytest.mark.asyncio
-async def test_save_task_event_metadata_contextid_update(
+async def test_save_task_event_metadata_update(
     task_manager: TaskManager, mock_task_store: AsyncMock
 ) -> None:
-    """Test saving an metadata and context update for an existing task."""
+    """Test saving an updated metadata for an existing task."""
     initial_task = Task(**MINIMAL_TASK)
     mock_task_store.get.return_value = initial_task
     new_metadata = {"meta_key_test": "meta_value_test"}
-    new_context_id = 'new_context_id'
 
     event = TaskStatusUpdateEvent(
         taskId=MINIMAL_TASK['id'],
-        contextId=new_context_id,
+        contextId=MINIMAL_TASK['contextId'],
         metadata=new_metadata,
         status=TaskStatus(state=TaskState.working),
         final=False,
@@ -148,7 +147,6 @@ async def test_save_task_event_metadata_contextid_update(
 
     updated_task = mock_task_store.save.call_args.args[0]
     assert updated_task.metadata == new_metadata
-    assert updated_task.contextId == new_context_id
 
 
 @pytest.mark.asyncio