Implement DashScope ASR provider and enhance ASR service architecture

- Added DashScope ASR service implementation for real-time streaming.
- Updated ASR provider logic to support DashScope alongside existing providers.
- Enhanced runtime metadata resolution to include DashScope as a valid ASR provider.
- Modified configuration files and documentation to reflect the addition of DashScope.
- Introduced tests to validate DashScope integration and ASR service behavior.
- Refactored ASR service factory to accommodate new provider options and modes.

engine/tests/test_dashscope_asr_provider.py

@@ -0,0 +1,67 @@
+import asyncio
+
+import pytest
+
+from providers.asr.dashscope import DashScopeRealtimeASRService
+
+
+@pytest.mark.asyncio
+async def test_dashscope_asr_interim_event_emits_interim_transcript():
+    received = []
+
+    async def _on_transcript(text: str, is_final: bool) -> None:
+        received.append((text, is_final))
+
+    service = DashScopeRealtimeASRService(api_key="test-key", on_transcript=_on_transcript)
+    service._loop = asyncio.get_running_loop()
+    service._running = True
+
+    service._on_ws_event(
+        {
+            "type": "conversation.item.input_audio_transcription.text",
+            "stash": "你好世界",
+        }
+    )
+    await asyncio.sleep(0.05)
+
+    result = service._transcript_queue.get_nowait()
+    assert result.text == "你好世界"
+    assert result.is_final is False
+    assert received == [("你好世界", False)]
+
+
+@pytest.mark.asyncio
+async def test_dashscope_asr_final_event_emits_final_transcript_and_final_queue():
+    received = []
+
+    async def _on_transcript(text: str, is_final: bool) -> None:
+        received.append((text, is_final))
+
+    service = DashScopeRealtimeASRService(api_key="test-key", on_transcript=_on_transcript)
+    service._loop = asyncio.get_running_loop()
+    service._running = True
+    service._audio_sent_in_utterance = True
+
+    service._on_ws_event(
+        {
+            "type": "conversation.item.input_audio_transcription.completed",
+            "transcript": "最终识别结果",
+        }
+    )
+    await asyncio.sleep(0.05)
+
+    result = service._transcript_queue.get_nowait()
+    assert result.text == "最终识别结果"
+    assert result.is_final is True
+    assert service._final_queue.get_nowait() == "最终识别结果"
+    assert received == [("最终识别结果", True)]
+
+
+@pytest.mark.asyncio
+async def test_dashscope_wait_for_final_falls_back_to_latest_interim_on_timeout():
+    service = DashScopeRealtimeASRService(api_key="test-key")
+    service._audio_sent_in_utterance = True
+    service._last_interim_text = "部分结果"
+
+    text = await service.wait_for_final_transcription(timeout_ms=10)
+    assert text == "部分结果"