Refactor project structure and enhance backend integration

- Expanded package inclusion in `pyproject.toml` to support new modules.
- Introduced new `adapters` and `protocol` packages for better organization.
- Added backend adapter implementations for control plane integration.
- Updated main application imports to reflect new package structure.
- Removed deprecated core components and adjusted documentation accordingly.
- Enhanced architecture documentation to clarify the new runtime and integration layers.

engine/runtime/ports/__init__.py

@@ -0,0 +1,32 @@
+"""Port interfaces for runtime integration boundaries."""
+
+from runtime.ports.asr import ASRBufferControl, ASRInterimControl, ASRPort, ASRServiceSpec
+from runtime.ports.control_plane import (
+    AssistantRuntimeConfigProvider,
+    ControlPlaneGateway,
+    ConversationHistoryStore,
+    KnowledgeRetriever,
+    ToolCatalog,
+)
+from runtime.ports.llm import LLMCancellable, LLMPort, LLMRuntimeConfigurable, LLMServiceSpec
+from runtime.ports.service_factory import RealtimeServiceFactory
+from runtime.ports.tts import TTSPort, TTSServiceSpec
+
+__all__ = [
+    "ASRPort",
+    "ASRServiceSpec",
+    "ASRInterimControl",
+    "ASRBufferControl",
+    "AssistantRuntimeConfigProvider",
+    "ControlPlaneGateway",
+    "ConversationHistoryStore",
+    "KnowledgeRetriever",
+    "ToolCatalog",
+    "LLMCancellable",
+    "LLMPort",
+    "LLMRuntimeConfigurable",
+    "LLMServiceSpec",
+    "RealtimeServiceFactory",
+    "TTSPort",
+    "TTSServiceSpec",
+]