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/docs/ws_v1_schema_zh.md

@@ -7,9 +7,9 @@
 - 握手顺序、状态机、错误语义与实现细节。
 
 实现对照来源：
-- `models/ws_v1.py`
-- `core/session.py`
-- `core/duplex_pipeline.py`
+- `protocol/ws_v1/schema.py`
+- `runtime/session/manager.py`
+- `runtime/pipeline/duplex.py`
 - `app/main.py`
 
 ---