fix(alarm): cap the ring at the configured volume instead of the device max

The ring-scoped media override forced STREAM_MUSIC to the hardware
maximum, so the alarm's configured percentage was applied on top of a
maxed speaker: "50%" meant 50% of the phone's absolute maximum and
the fade rode against that ceiling, far louder than the device-
relative level users were used to. On-device logcat also showed the
just_audio player emitting one buffer at volume 1.0 before the 5%
pre-start took effect, a full-scale click on the maxed stream.

The stream is now capped at the alarm's configured volume (still
independent of the device's own level, so it rings at device-volume
0), and the player ramps from ~5% up to its full range under that
cap. Perceived peak is the configured fraction of the device maximum,
reached gradually; the opening click drops to the configured fraction
instead of full scale.

lib/app.dart

@@ -378,8 +378,15 @@ class _PaginaPrincipalState extends State<_PaginaPrincipal> {
     // effect for the whole ring, including fallback-WAV-only alarms that
     // never reach the station-playback branch below (Requirement:
     // Ring-scoped device-volume override).
+    //
+    // The media stream is capped at the alarm's CONFIGURED volume, not the
+    // device max: this makes the ring independent of the device's own volume
+    // (audible even at 0) while keeping "50%" meaning 50% of the phone's
+    // maximum. The player then ramps from ~5% up to full under this cap, so
+    // the perceived peak is exactly the configured fraction of max, reached
+    // gradually — not the device-relative level, and not a full-blast max.
     await context.read<EstadoAlarmas>().android.forzarVolumenMediaParaAlarma(
-      1.0,
+      alarma.volumen.clamp(0.0, 1.0),
     );
     if (!mounted) return;
     final emisora = alarma.emisora;