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/api/platform/event.py

@@ -16,8 +16,8 @@ import datetime
 from pydantic import BaseModel, Field, ConfigDict
 from ulid import ULID
 from typing import Any, Dict
-from kilostar.core.workflow_running_engine.workflow import kilostarWorkflow
 import asyncio
+from kilostar.core.work.workflow.workflow import KiloStarWorkflow
 
 
 class kilostarEvent(BaseModel):
@@ -43,7 +43,7 @@ class kilostarEvent(BaseModel):
     context: Dict[str, Any] = Field(
         default_factory=dict, description="事件上下文内容，可包含工作流模板等信息"
     )
-    workflow: kilostarWorkflow | None = Field(default=None, description="工作流")
+    workflow: KiloStarWorkflow | None = Field(default=None, description="工作流")
     pending_queue: asyncio.Queue[str] | None = Field(
         default=None, description="待处理队列"
     )