fix(dashboard): correct stage key mismatch, add created_at, persist cancelled tasks

- Fix ANALYSIS_STAGES key 'trader' → 'trading' to match backend STAGE markers
- Add created_at field to task state at creation, sort list_tasks by it
- Persist task state before broadcast in cancel path (closes restart race)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

web_dashboard/backend/main.py

@@ -231,6 +231,7 @@ async def start_analysis(request: AnalysisRequest):
         "status": "running",
         "progress": 0,
         "current_stage": "analysts",
+        "created_at": datetime.now().isoformat(),
         "elapsed": 0,
         "stages": [
             {"status": "running", "completed_at": None},
@@ -419,10 +420,10 @@ async def list_tasks():
             "progress": state.get("progress", 0),
             "decision": state.get("decision"),
             "error": state.get("error"),
-            "created_at": state.get("stages", [{}])[0].get("completed_at") if state.get("stages") else None,
+            "created_at": state.get("created_at"),
         })
-    # Sort by task_id (which includes timestamp) descending
-    tasks.sort(key=lambda x: x["task_id"], reverse=True)
+    # Sort by created_at descending (most recent first)
+    tasks.sort(key=lambda x: x.get("created_at") or "", reverse=True)
     return {"tasks": tasks, "total": len(tasks)}
 
 
@@ -446,6 +447,7 @@ async def cancel_task(task_id: str):
         task.cancel()
         app.state.task_results[task_id]["status"] = "failed"
         app.state.task_results[task_id]["error"] = "用户取消"
+        _save_task_status(task_id, app.state.task_results[task_id])
         await broadcast_progress(task_id, app.state.task_results[task_id])
 
     # Clean up temp script

web_dashboard/frontend/src/pages/AnalysisMonitor.jsx

@@ -6,7 +6,7 @@ import { CheckCircleOutlined, SyncOutlined, CloseCircleOutlined } from '@ant-des
 const ANALYSIS_STAGES = [
   { key: 'analysts', label: '分析师团队' },
   { key: 'research', label: '研究员辩论' },
-  { key: 'trader', label: '交易员' },
+  { key: 'trading', label: '交易员' },
   { key: 'risk', label: '风险管理' },
   { key: 'portfolio', label: '组合经理' },
 ]