Add Qingdao to the tradable city network

Qingdao needs the same airport-settlement path as the other Wunderground-backed APAC cities, so the registry, aliases, timezone, prewarm, official links, market focus, and tests now point to ZSQD / Qingdao Jiaodong International Airport.

Constraint: User supplied Wunderground Qingdao/ZSQD settlement URL.
Rejected: Add a partial registry-only entry | it would show in APIs without frontend links, prewarm coverage, or alias support.
Confidence: high
Scope-risk: narrow
Reversibility: clean
Tested: pytest tests/test_country_networks.py tests/test_web_observability.py::test_cities_endpoint_includes_new_wunderground_cities -q
Tested: npm run build
Not-tested: Live Wunderground fetch for ZSQD in production.

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## 1.5.5 - 2026-04-27
 
+- 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