Clarify staged AI bulletin reads for city cards

Users saw fast-rule evidence, partial streams, DeepSeek completion, and fallback states as one blended AI status. The city evidence panel now names the current stage directly so a loading stream reads as fast judgment complete, a successful response reads as AI bulletin read complete, and incomplete responses explain that rule evidence is being used.

Constraint: Keep the existing fast evidence path visible while DeepSeek streams in.
Rejected: Label fallback as an AI failure | that incorrectly implies the card is broken even when rule evidence is valid.
Confidence: high
Scope-risk: narrow
Reversibility: clean
Tested: npm run build
Not-tested: Manual browser timing of partial stream transitions.

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 - 新增 Qingdao / 青岛城市，结算锚点接入 Wunderground 青岛胶东国际机场 `ZSQD` 历史页，并补齐别名、时区、预热、官方来源和前端地区归类
 - 城市决策卡顶部状态标签收口为 2-3 个高优先级信号，优先展示“实测突破 / 峰值窗口已过 / METAR 过旧 / AI 解读中 / 市场价格缺失 / 模型高度一致 / 需要等待下一报文”，让用户第一眼看到重点
+- 城市决策卡 AI 机场报文区明确拆分“快速判断已完成，AI 正在补充机场报文细节… / AI 机场报文解读已完成 / AI 解读未完整返回，当前使用规则证据”三种状态，减少 fallback 与流式返回造成的误解
 - 城市决策卡新增 AI 机场报文解读缓存说明：页面内存缓存保留 loading / 流式片段 / 最终结果，`localStorage` 保存最终成功 payload，后端 AI 缓存不再因 `local_time` 变化失效
 - 城市决策卡兜底文案明确标记“快速证据模式”，避免在 DeepSeek 未完整返回时误写成“AI 机场报文解读正常”
 - 城市决策卡流式 AI 解读改为只请求 METAR/官方观测核心解读与判断依据，最高温中枢、模型一致性和风险清单由后端规则补齐，减少等待时间