[WIP][Bugfix][MiniCPM-o] Fix Full duplex bugs for minicpm-challenge (#5496)

Signed-off-by: Sy03 <1370724210@qq.com>

tests/engine/test_multimodal_accumulation.py

@@ -18,6 +18,7 @@ def test_chunk_accumulation_policy_replaces_snapshots_and_drains_delta_state():
     accumulated = MultimodalPayload.from_dict(
         {
             "audio": torch.tensor([1.0]),
+            "meta.segment_end": torch.tensor([0]),
             "meta.tts_is_last_chunk": torch.tensor([0]),
             "meta.turn_end": torch.tensor([0]),
             "meta.stable_request_value": "keep",
@@ -26,6 +27,7 @@ def test_chunk_accumulation_policy_replaces_snapshots_and_drains_delta_state():
     incoming = MultimodalPayload.from_dict(
         {
             "audio": torch.tensor([2.0]),
+            "meta.segment_end": torch.tensor([1]),
             "meta.tts_is_last_chunk": torch.tensor([1]),
             "meta.turn_end": torch.tensor([1]),
         }
@@ -41,6 +43,7 @@ def test_chunk_accumulation_policy_replaces_snapshots_and_drains_delta_state():
     drain_delta_payload(merged)
 
     assert "audio" not in merged
+    assert "meta.segment_end" not in merged
     assert "meta.tts_is_last_chunk" not in merged
     assert "meta.turn_end" not in merged
     assert merged.metadata["meta.stable_request_value"] == "keep"