逐任务真实成本：上游用量事件 + 价目表计价

此前每任务只记一条 estimated（字符数/4，金额为空），注释称
host 协议不暴露真实 token 数。本轮实测推翻了该前提：
- account/usage/read 在中继上是死的（要求 ChatGPT 账号登录），
  不是来源，已在 cost.py docstring 写明死胡同
- app-server 每上游补全发 thread/tokenUsage/updated，last 是该次
  补全的用量；中继 5 调用回合实测 last 之和等于最后 total
  （input/output/cached/reasoning 四路都对得上）

实现：host.py run_turn 从事件窗口按 threadId+turnId 汇总用量，
重试/goal 各轮累加，dispatch/run JSON 与 goal 用量行透传；
sandbox 三路解析（dispatch JSON 解析改用完整 stdout，顺带修
了长 text 下 failed 被误判 completed 的潜 bug）；worker 每任务
记一条 actual（重试/fallback 用量累加进同一条），无用量时回落
estimated；cost.py 价目表（默认 OpenAI 挂牌价，env 可覆盖，
无价模型 usd 记 None、报表进 unpriced_actual_tokens 而非 0 美元），
cost_records 加 cached_input_tokens 列（SQLite/PG 两支迁移）；
报表与按天行新增 cached_input_tokens/unpriced_actual_tokens。
测试：host 32、cloud 483 全过。

cloud/tests/test_models_cost.py

@@ -8,13 +8,15 @@ import os
 import sys
 import unittest
 from datetime import datetime, timezone
+from unittest import mock
 
 # cloud/ has no __init__.py by design (the coordinator creates it), so
 # make the project root importable regardless of the discover top level.
 sys.path.insert(0, os.path.dirname(os.path.dirname(
     os.path.dirname(os.path.abspath(__file__)))))
 
-from cloud.cost import CostStore, estimate_tokens, fetch_account_usage
+from cloud.cost import (CostStore, estimate_tokens, fetch_account_usage,
+                        price_usd_micros)
 from cloud.models import FALLBACKABLE, ModelRouter, is_fallbackable, record_fallback
 
 
@@ -192,8 +194,80 @@ class TestCostStore(unittest.TestCase):
             "fallback_count": 0,
             "actual_tokens": 0,
             "estimated_tokens": 0,
+            "cached_input_tokens": 0,
+            "unpriced_actual_tokens": 0,
         })
 
 
+class TestModelPrices(unittest.TestCase):
+    def test_list_prices(self):
+        # 2026-10-26 中继实测 5 调用回合：(58243-45960)*2
+        # + 45960*0.10 + 1138*10 = 40542 微美元。
+        self.assertEqual(
+            price_usd_micros("gpt-6.1-sol", 58243, 45960, 1138), 40542)
+        self.assertEqual(
+            price_usd_micros("gpt-6-sol", 1000, 200, 100),
+            int(round((800 * 2.00 + 200 * 0.20 + 100 * 10.00))))
+
+    def test_unknown_model_unpriced(self):
+        self.assertIsNone(price_usd_micros("gpt-5.6-sol", 100, 0, 100))
+        self.assertIsNone(price_usd_micros(None, 100, 0, 100))
+
+    def test_cached_clamped_to_input(self):
+        self.assertEqual(
+            price_usd_micros("gpt-6.1-sol", 100, 500, 100),
+            price_usd_micros("gpt-6.1-sol", 100, 100, 100))
+
+    def test_env_override(self):
+        with mock.patch.dict(os.environ, {
+                "CLOUD_MODEL_PRICES_JSON":
+                    '{"gpt-6.1-sol": [4.00, 0.20, 20.00]}'}):
+            self.assertEqual(
+                price_usd_micros("gpt-6.1-sol", 1000, 0, 0), 4000)
+        with mock.patch.dict(os.environ, {
+                "CLOUD_MODEL_PRICES_JSON": 'not json'}):
+            # 坏覆盖不炸，回落默认表。
+            self.assertEqual(
+                price_usd_micros("gpt-6.1-sol", 1000, 0, 0), 2000)
+
+
+class TestCachedColumn(unittest.TestCase):
+    def test_record_keeps_cached_and_unpriced(self):
+        store = CostStore(":memory:")
+        store.record("t1", "p1", "gpt-6.1-sol", input_tokens=1000,
+                     output_tokens=100, cached_input_tokens=400,
+                     usd_micros=2240, source="actual")
+        store.record("t2", "p1", "gpt-5.6-sol", input_tokens=500,
+                     output_tokens=50, cached_input_tokens=0,
+                     usd_micros=None, source="actual")
+        report = store.report_by_project("p1")
+        self.assertEqual(report["cached_input_tokens"], 400)
+        self.assertEqual(report["unpriced_actual_tokens"], 550)
+        self.assertEqual(report["usd_micros"], 2240)
+
+    def test_migration_adds_cached_column_to_old_table(self):
+        import sqlite3
+        import tempfile
+        path = os.path.join(tempfile.mkdtemp(), "c.db")
+        conn = sqlite3.connect(path)
+        conn.execute(
+            "CREATE TABLE cost_records (id INTEGER PRIMARY KEY"
+            " AUTOINCREMENT, task_id TEXT, project_id TEXT, model TEXT,"
+            " input_tokens INTEGER, output_tokens INTEGER,"
+            " total_tokens INTEGER, usd_micros INTEGER, source TEXT,"
+            " fallback_count INTEGER DEFAULT 0, day TEXT,"
+            " created_at REAL)")
+        conn.commit()
+        conn.close()
+        store = CostStore(path)
+        cols = {row[1] for row in store._conn.execute(
+            "PRAGMA table_info(cost_records)").fetchall()}
+        self.assertIn("cached_input_tokens", cols)
+        store.record("t1", "p1", "m", input_tokens=10, output_tokens=5,
+                     cached_input_tokens=3, source="actual")
+        self.assertEqual(store.report_by_task("t1")["cached_input_tokens"],
+                         3)
+
+
 if __name__ == "__main__":
     unittest.main()