fix(android): target API level 35 as required by Google Play

Play rejected version code 54 for still targeting 34.

From API 35 Android forces edge-to-edge: content is drawn behind the system
bars and it is up to each screen to keep clear of them. Seven screens had no
SafeArea and their bottom action button would have ended up under the
gesture bar, so FondoFarolero gains a respetarBarras flag that insets the
content while the background still paints full bleed. The seventeen screens
that already handle it are untouched.

The navigation bar colour is ignored under edge-to-edge, so its icons are
now forced light to stay visible over the dark background.

Verified on the merged manifest: targetSdkVersion 35, and the release bundle
builds. The visual result has not been checked on a device.

android/app/build.gradle.kts

@@ -30,7 +30,10 @@ android {
     defaultConfig {
         applicationId = "es.freetimelab.farolero.game"
         minSdk = 24
-        targetSdk = 34
+        // Google Play exige 35 como mínimo. A partir de aquí Android impone el
+        // dibujado de borde a borde: el contenido va detrás de las barras del
+        // sistema y son las pantallas las que deben apartarse.
+        targetSdk = 35
         versionCode = flutter.versionCode
         versionName = flutter.versionName
     }