Refactor Workflow and Chat Architecture (#68)

* refactor: overhaul workflow and chat architecture

- Separate Chat and Workflow API endpoints and database models
- Use JSONB to store workflow execution context in Postgres
- Convert workflow engine to use pydantic-ai execution graphs inside a Ray task
- Update frontend React components to support standalone workflow creation
- Remove obsolete and broken workflow runner tests

Co-authored-by: zhaoxi826 <198742034+zhaoxi826@users.noreply.github.com>

* refactor: overhaul workflow and chat architecture

- Separate Chat and Workflow API endpoints and database models
- Use JSONB to store workflow execution context in Postgres
- Convert workflow engine to use pydantic-ai execution graphs inside a Ray task
- Update frontend React components to support standalone workflow creation
- Remove obsolete and broken workflow runner tests

Co-authored-by: zhaoxi826 <198742034+zhaoxi826@users.noreply.github.com>

* refactor: overhaul workflow and chat architecture

- Separate Chat and Workflow API endpoints and database models
- Use JSONB to store workflow execution context in Postgres
- Convert workflow engine to use pydantic-ai execution graphs inside a Ray task
- Update frontend React components to support standalone workflow creation
- Move workflow_engine inside workflow package to keep core root clean
- Remove obsolete and broken workflow runner tests

Co-authored-by: zhaoxi826 <198742034+zhaoxi826@users.noreply.github.com>

---------

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>
Co-authored-by: zhaoxi826 <198742034+zhaoxi826@users.noreply.github.com>

kilostar/core/individual/control_node/template.py

@@ -14,7 +14,7 @@
 
 
 from pydantic import Field
-from kilostar.core.workflow_running_engine.workflow import WorkStep
+from kilostar.core.work.workflow.workflow import WorkflowStep
 from kilostar.utils.agent_model import ResponseModel, InputModel, DepsModel
 
 
@@ -35,7 +35,8 @@ class ControlNodeDeps(DepsModel):
     """ControlNodeDeps 核心组件类。
     这是一个系统执行节点类，作为多智能体架构中的独立处理单元。它能够接收工作流上下文，根据内置的大模型策略进行意图理解和自主决策，从而驱动特定阶段的任务闭环。"""
 
-    workflow_step: WorkStep
+    workflow_step: WorkflowStep
+    workflow_step: WorkflowStep
     # In the future, this can be dynamically populated with tools specific to the current task execution
 
 
@@ -52,4 +53,4 @@ class ForWorkflowInput(ControlNodeInput):
     """ForWorkflowInput 核心组件类。
     这是一个领域数据模型或功能封装类，承载了 ForWorkflowInput 相关的内聚属性定义与状态维护。它的存在隔离了局部的业务复杂性，并对外提供了类型安全的访问接口。"""
 
-    workflow_step: WorkStep
+    workflow_step: WorkflowStep