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_asr_factory_modes.py

@@ -0,0 +1,46 @@
+from providers.asr.buffered import BufferedASRService
+from providers.asr.dashscope import DashScopeRealtimeASRService
+from providers.asr.openai_compatible import OpenAICompatibleASRService
+from providers.factory.default import DefaultRealtimeServiceFactory
+from runtime.ports import ASRServiceSpec
+
+
+def test_create_asr_service_dashscope_returns_streaming_provider():
+    factory = DefaultRealtimeServiceFactory()
+    service = factory.create_asr_service(
+        ASRServiceSpec(
+            provider="dashscope",
+            mode="streaming",
+            sample_rate=16000,
+            api_key="test-key",
+            model="qwen3-asr-flash-realtime",
+        )
+    )
+    assert isinstance(service, DashScopeRealtimeASRService)
+    assert service.mode == "streaming"
+
+
+def test_create_asr_service_openai_compatible_returns_offline_provider():
+    factory = DefaultRealtimeServiceFactory()
+    service = factory.create_asr_service(
+        ASRServiceSpec(
+            provider="openai_compatible",
+            sample_rate=16000,
+            api_key="test-key",
+            model="FunAudioLLM/SenseVoiceSmall",
+        )
+    )
+    assert isinstance(service, OpenAICompatibleASRService)
+    assert service.mode == "offline"
+
+
+def test_create_asr_service_fallback_buffered_for_unsupported_provider():
+    factory = DefaultRealtimeServiceFactory()
+    service = factory.create_asr_service(
+        ASRServiceSpec(
+            provider="unknown_provider",
+            sample_rate=16000,
+        )
+    )
+    assert isinstance(service, BufferedASRService)
+    assert service.mode == "offline"