feat: cost/quota set — dual-column priced reports, creator split, hard cutoff, approval-timeout auto-threshold

- CostStore: per-model breakdown, report_by_creator (JOIN tasks.created_by),
  dual-column reports with priced_usd_micros, unpriced_models listed
  separately and a billing note (proxy price, not the relay bill);
  _report itself untouched, old exact-key tests keep passing.
- Hard cutoff: cost.quota_cutoff_reason is the single USD/unpriced-cap
  decision; worker._quota_exceeded now delegates to it (identical
  messages); claim gate, turn boundary and poll kill stop spend and
  record interrupted + quota reason + audit; auto-resume re-checks
  live quota before requeueing.
- Approval timeout (G7 ops metric): cloud/approval_timeout.py —
  default stays 600s, >20% timeout rate recommends 1800s, <5% keeps,
  mid-range keeps; stats + recommendation + info log; wired into
  /metrics (member projects, no log spam) and a global-admin
  /admin/ops/approval-timeout endpoint (sweeps overdue first).
- Server: task/project cost endpoints return dual-column reports;
  new GET /users/me/cost and GET /admin/cost-by-creator.
- Tests: cloud/tests/test_cost_quota.py, 10 tests.

cloud/worker.py

@@ -142,7 +142,7 @@ from cloud.coordinator import ensure_columns as _coord_ensure_columns
 from cloud.coordinator import parse_parts as _coord_parse_parts
 from cloud.coordinator import nonterminal_children as _coord_nonterminal
 from cloud.cost import CostStore, estimate_tokens, price_usd_micros, \
-    sum_usage, unpriced_token_cap
+    quota_cutoff_reason, sum_usage
 from cloud.db import connect as _db_connect
 from cloud.goal_command import parse_goal_command as _parse_goal_command
 from cloud.logging_config import get_logger, log_event, setup_logging
@@ -2155,15 +2155,11 @@ class Worker:
                 unpriced_used += (
                     max(0, int(usage_total.get("input_tokens", 0)))
                     + max(0, int(usage_total.get("output_tokens", 0))))
-        if used >= quota:
-            return ("quota_exceeded: 本月配额已用完（已用 %d / "
-                    "配额 %d 微美元，%s）" % (used, quota, month))
-        cap = unpriced_token_cap()
-        if unpriced_used >= cap:
-            return ("quota_exceeded: 本月无价模型 token 已用完"
-                    "（已用 %d / 上限 %d，%s）"
-                    % (unpriced_used, cap, month))
-        return None
+        # 硬切断判定收敛到 cost.quota_cutoff_reason：USD 配额与
+        # 无价上限任一超限即回 quota_exceeded 文本，调用方（认领
+        # 门、轮次边界、30 秒轮询）据此停掉任务、不再开新回合；
+        # 文本与旧分支逐字一致，旧单测按此前缀断言。
+        return quota_cutoff_reason(quota, used, unpriced_used, month)
 
     def _ready_tasks(self):
         """当前就绪任务列表（pick_next 的批量版）。