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/runtime/ports/__init__.py

@@ -1,6 +1,12 @@
 """Port interfaces for runtime integration boundaries."""
 
-from runtime.ports.asr import ASRBufferControl, ASRInterimControl, ASRPort, ASRServiceSpec
+from runtime.ports.asr import (
+    ASRMode,
+    ASRPort,
+    ASRServiceSpec,
+    OfflineASRPort,
+    StreamingASRPort,
+)
 from runtime.ports.control_plane import (
     AssistantRuntimeConfigProvider,
     ControlPlaneGateway,
@@ -13,10 +19,11 @@ from runtime.ports.service_factory import RealtimeServiceFactory
 from runtime.ports.tts import TTSPort, TTSServiceSpec
 
 __all__ = [
+    "ASRMode",
     "ASRPort",
     "ASRServiceSpec",
-    "ASRInterimControl",
-    "ASRBufferControl",
+    "OfflineASRPort",
+    "StreamingASRPort",
     "AssistantRuntimeConfigProvider",
     "ControlPlaneGateway",
     "ConversationHistoryStore",