今日实测最高改用 airport_current.max_so_far（METAR历史观测）

项目已有 airport_current 字段存储 METAR/AMOS 当天最高温及时间，
无需从 obs_log 自建。obs_log 保留期恢复为 2 小时。

Tested: pytest 176 passed, ruff check 通过

src/database/db_manager.py

@@ -1861,7 +1861,7 @@ class DBManager:
                  temp_c, wind_kt, pressure_hpa, str(obs_time)),
             )
             conn.execute(
-                "DELETE FROM airport_obs_log WHERE created_at < datetime('now', '-24 hours')"
+                "DELETE FROM airport_obs_log WHERE created_at < datetime('now', '-2 hours')"
             )
             conn.commit()
 

src/utils/telegram_push.py

@@ -763,38 +763,24 @@ def _build_airport_status_message(
         lines.append(f"当前实测：{station_temp:.1f}°C")
     if deb_pred is not None:
         lines.append(f"今日DEB预报最高：{deb_pred:.1f}°C")
-    max_so_far, max_temp_time = _get_airport_daily_high(city)
+    max_so_far, max_temp_time = _get_airport_daily_high(city_weather)
     if max_so_far is not None:
         time_str = f"（{max_temp_time}）" if max_temp_time else ""
         lines.append(f"今日实测最高：{max_so_far:.1f}°C{time_str}")
     return "\n".join(lines)
 
 
-def _get_airport_daily_high(city: str):
-    """Get today's observed high from airport_obs_log for this city."""
-    icao = HIGH_FREQ_AIRPORT_ICAO.get(city, "")
-    if not icao:
-        return None, None
-    try:
-        from src.database.db_manager import DBManager
-        db = DBManager()
-        obs = db.get_airport_obs_recent(icao, minutes=1440)  # last 24h
-        if not obs:
-            return None, None
-        best = max(obs, key=lambda r: r.get("temp_c") or -999)
-        temp_c = best.get("temp_c")
-        obs_time = best.get("obs_time") or ""
-        if temp_c is None:
-            return None, None
+def _get_airport_daily_high(city_weather: Dict[str, Any]):
+    """Get today's observed high from METAR/AMOS airport history."""
+    airport = city_weather.get("airport_current") or {}
+    max_so_far = airport.get("max_so_far")
+    max_time = airport.get("max_temp_time")
+    if max_so_far is not None:
         try:
-            from datetime import datetime
-            dt = datetime.fromisoformat(str(obs_time))
-            time_str = dt.strftime("%H:%M")
+            max_so_far = round(float(max_so_far), 1)
         except Exception:
-            time_str = str(obs_time)[:5] if obs_time else ""
-        return round(float(temp_c), 1), time_str
-    except Exception:
-        return None, None
+            max_so_far = None
+    return max_so_far, max_time
 
 
 # Per-city push interval matching native data refresh rate (seconds)