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.

src/data_collection/city_registry.py

@@ -715,6 +715,24 @@ CITY_REGISTRY = {
         "distance_km": 28.0,
         "warning": "市场现按 Wunderground 广州白云国际机场站整度°C口径结算；珠三角海陆风与午后对流会让峰值兑现时间出现摇摆。",
     },
+    "qingdao": {
+        "name": "Qingdao",
+        "lat": 36.3620,
+        "lon": 120.0882,
+        "icao": "ZSQD",
+        "settlement_source": "wunderground",
+        "settlement_station_code": "ZSQD",
+        "settlement_station_label": "Qingdao Jiaodong International Airport Station",
+        "settlement_url": "https://www.wunderground.com/history/daily/cn/qingdao/ZSQD",
+        "tz_offset": 28800,
+        "use_fahrenheit": False,
+        "is_major": True,
+        "risk_level": "medium",
+        "risk_emoji": "🟡",
+        "airport_name": "青岛胶东国际机场",
+        "distance_km": 39.0,
+        "warning": "市场现按 Wunderground 青岛胶东国际机场站整度°C口径结算；沿海海风、低云和海雾会影响日内升温效率。",
+    },
     "beijing": {
         "name": "Beijing",
         "lat": 40.0801,
@@ -918,12 +936,17 @@ ALIASES = {
     "ckg": "chongqing", "cq": "chongqing",
     "szx": "shenzhen", "sz": "shenzhen",
     "can": "guangzhou", "gz": "guangzhou", "zggg": "guangzhou",
+    "tao": "qingdao", "qdo": "qingdao", "qingdao": "qingdao", "zsqd": "qingdao",
     "pek": "beijing", "bjs": "beijing", "bj": "beijing",
     "wuh": "wuhan", "wh": "wuhan",
     "成都": "chengdu",
     "重庆": "chongqing",
     "深圳": "shenzhen",
     "广州": "guangzhou",
+    "青岛": "qingdao",
+    "青島": "qingdao",
+    "青岛胶东": "qingdao",
+    "青島膠東": "qingdao",
     "北京": "beijing",
     "武汉": "wuhan",
 }