fix(web): Y按鈕簽核回應解析錯誤 - result.status → result.approval.status

根因: API 回傳 {approval: {status: 'approved'}} 但前端誤檢查 result.status

修復:
- dual-state-incident-card.tsx: 正確解析 result.approval.status
- api-client.ts: 更新回傳型別與後端對齊

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/web/src/lib/api-client.ts

@@ -124,12 +124,17 @@ export const apiClient = {
         comment: comment,
       }),
     })
+    // 🔧 Fix: 回傳型別與後端實際結構對齊
     return handleResponse<{
-      approval_id: string
-      status: string
-      current_signatures: number
-      required_signatures: number
+      success: boolean
       message: string
+      approval: ApprovalResponse
+      execution_triggered: boolean
+      // 向下相容舊欄位 (deprecated)
+      approval_id?: string
+      status?: string
+      current_signatures?: number
+      required_signatures?: number
     }>(res)
   },