v2.4.0: Night dimming, aircraft watchlist, and nearest-airport lookup

src/airport_lookup.h

@@ -0,0 +1,12 @@
+#pragma once
+#include <Arduino.h>
+
+namespace AirportLookup {
+    struct Nearest {
+        bool found = false;
+        char icao[5] = {0};
+        char name[32] = {0};
+        float distanceKm = 0;
+    };
+    Nearest findNearest(double lat, double lon);
+}