feat(agent): budget reminders, usage while waiting, budget-exceeded status and dedupe

- tool results carry a budget reminder near limits; text before the last tool
  call is dropped as report when cut by budget/abort
- usage persisted when a run suspends, so waiting sessions show spent tokens
- task page shows budget_exceeded via business.outcome instead of completed
- budget-exceeded decisions merge by root cause (decision / schedule / goal
  template); new summaries added to investigate allowlist

Co-Authored-By: Claude Opus 5.5 <[email protected]>

packages/contracts/src/ops.ts

@@ -270,6 +270,11 @@ export const EngineRunBusiness = z.object({
   /** 展示名(订阅/作品标题、下载任务名、Feed/站点名、会话目标等);对象已删除时为 null */
   title: z.string().nullable(),
   triggeredBy: EngineTriggeredBy.nullable(),
+  /**
+   * 业务结果(与引擎状态不同时才有意义):Agent 会话为 agent_run.status。引擎 run 正常结束而会话超出预算 / 失败时,
+   * 任务页按它显示「超出预算」/「失败」,不显示「完成」
+   */
+  outcome: z.string().nullable().optional(),
 });
 export type EngineRunBusiness = z.infer<typeof EngineRunBusiness>;