Scrolling marquee for radar info line, clearer tap hint text

The bottom info line on the radar screen (tap hint / empty-sky timer)
is now a continuously scrolling marquee instead of static text,
consistent with the nearest-airport ticker on the Location Presets
screen. The text is redrawn every tick() call (80ms) rather than only
on render(), so it scrolls smoothly and the empty-sky second counter
keeps advancing fluidly.

Also clarifies the tap hint in all 6 languages to make it explicit
that you need to tap an aircraft (e.g. "Tap an aircraft for more
details" instead of the more ambiguous "Tap for details").

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/i18n_es.h

@@ -133,7 +133,7 @@ static const char* const I18N_ES[] = {
     "El dispositivo también ofrece una pequeña página web para exportar el registro completo. Conectado a la misma red WiFi, simplemente abra un navegador y vaya a:",
     "Sin conexión WiFi - la página de exportación solo es accesible mientras haya una conexión de red.",
 
-    "Toque para ver detalles",
+    "Toque un avión para ver más detalles",
     "Cielo vacío desde hace ",
 
     "Modelo: ",