Make city decision cards easier to trust at a glance

The decision card now exposes deterministic guard state, data freshness, AI readiness and market sync directly in the card header so users can understand whether they are looking at fresh evidence, a fallback, or a stale/exception case before reading the full explanation.

Constraint: Keep the first useful read available while DeepSeek airport/HKO details are still streaming.\nRejected: Add another expanded evidence panel | header-level badges are faster to scan and avoid increasing card depth.\nConfidence: high\nScope-risk: narrow\nReversibility: clean\nTested: npm run build\nNot-tested: Browser visual QA on production data.

CHANGELOG.md

@@ -9,6 +9,7 @@
 - 城市决策卡兜底判断补充实测偏低和峰值窗口已过分支：峰后未追上模型时提示下修压力，峰前偏低时只提示等待确认
 - 城市决策卡新增过旧 METAR/观测识别：过旧报文只作为背景参考，不再触发强实况锚点、上修或下修判断；AI 缓存键同步纳入观测时间与 stale 状态
 - 城市决策卡新增 AI 结果后处理护栏：完整 DeepSeek 返回若与过旧观测、实测突破、峰后下修等确定性证据冲突，会以后端规则覆盖关键数值和结论文案
+- 城市决策卡新增状态标签与数据新鲜度提示，直接标出 AI 是否完成、市场价格是否同步、METAR/官方观测是否过旧或已突破模型区间，减少用户等待和误读
 - 后端 Scan Terminal 代码拆出 `scan_city_ai_helpers.py`，将城市 AI JSON 解析、fallback 文案、schema completion 与证据护栏从主服务文件中剥离，降低后续维护成本
 - 城市决策卡市场层改用完整 `all_buckets` 并严格识别 exact / range / or higher / or lower 温度桶方向，避免最高温中枢错配到不合理尾部桶
 - 温度桶标签统一规范化 `C/F/°C/°F`，修复 `31°°C` 这类重复单位展示