fix(alarm): avoid ClassCastException casting snooze millis to Long

Flutter's StandardMethodCodec encodes Dart ints that fit in 32 bits as
Java Integer, not Long. scheduleAlarm sends preNoticeAtMillis=0 when
rescheduling a snooze, which crashed the unchecked argument<Long>()
cast. Read all millis args as Number and convert with toLong().

android/app/src/main/kotlin/es/freetimelab/pluriwave/MainActivity.kt

@@ -80,8 +80,8 @@ class MainActivity : AudioServiceActivity() {
                 "scheduleAlarm" -> {
                     val id = call.argument<String>("id")
                     val title = call.argument<String>("title") ?: "PluriWave"
-                    val triggerAtMillis = call.argument<Long>("triggerAtMillis")
-                    val preNoticeAtMillis = call.argument<Long>("preNoticeAtMillis") ?: 0L
+                    val triggerAtMillis = call.argument<Number>("triggerAtMillis")?.toLong()
+                    val preNoticeAtMillis = call.argument<Number>("preNoticeAtMillis")?.toLong() ?: 0L
                     val stationName = call.argument<String>("stationName")
                     val stationUrl = call.argument<String>("stationUrl")
                     val fallbackSound = call.argument<String>("fallbackSound")
@@ -107,10 +107,10 @@ class MainActivity : AudioServiceActivity() {
                             minute = call.argument<Int>("minute"),
                             scheduleType = call.argument<String>("scheduleType"),
                             weekdays = weekdays,
-                            oneShotDateMillis = call.argument<Long>("oneShotDateMillis"),
-                            snoozeUntilMillis = call.argument<Long>("snoozeUntilMillis"),
-                            snoozeOriginMillis = call.argument<Long>("snoozeOriginMillis"),
-                            lastHandledAtMillis = call.argument<Long>("lastHandledAtMillis"),
+                            oneShotDateMillis = call.argument<Number>("oneShotDateMillis")?.toLong(),
+                            snoozeUntilMillis = call.argument<Number>("snoozeUntilMillis")?.toLong(),
+                            snoozeOriginMillis = call.argument<Number>("snoozeOriginMillis")?.toLong(),
+                            lastHandledAtMillis = call.argument<Number>("lastHandledAtMillis")?.toLong(),
                             soundOnVacation = call.argument<Boolean>("soundOnVacation") ?: true,
                             snoozeMinutes = call.argument<Int>("snoozeMinutes") ?: 5,
                             fallbackStationName = call.argument<String>("fallbackStationName"),