fix(audio): show intensity profile for sound-only alerts; enforce TTS min volume

- CommonAlertSettings: intensity profile (SOFT/STEADY/STRONG/ESCALATING)
  was hidden behind vibration toggle; now shown whenever sound OR vibration
  is enabled, since it controls both sound ceiling and haptic amplitude.
  Label changed from "Haptics" to "Intensity" to reflect dual role.

- Talker: add ensureMinStreamVolume() called before every engine.speak().
  If the active stream (notification/media/alarm) is below 25% of its max,
  it is raised to that floor before speaking. Prevents spoken readings from
  going silent when the user sets media volume to zero.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: Rob

Common/src/main/java/tk/glucodata/Talker.java

@@ -479,9 +479,37 @@ public void onStart(String utteranceId) {
         }
    }
 
+// Fraction of the stream's max volume that is the minimum allowed for TTS output.
+// Prevents silence when the user (or system) drives the stream to zero.
+private static final float MIN_TTS_VOLUME_FRACTION = 0.25f;
+
+private static int usageToStreamType(int usage) {
+    switch (usage) {
+        case AudioAttributes.USAGE_ALARM:  return AudioManager.STREAM_ALARM;
+        case AudioAttributes.USAGE_MEDIA:  return AudioManager.STREAM_MUSIC;
+        default:                           return AudioManager.STREAM_NOTIFICATION;
+    }
+}
+
+private static void ensureMinStreamVolume() {
+    try {
+        AudioManager am = (AudioManager) Applic.app.getSystemService(Context.AUDIO_SERVICE);
+        if (am == null) return;
+        final int stream = usageToStreamType(Natives.getSoundType());
+        final int maxVol = am.getStreamMaxVolume(stream);
+        final int minVol = Math.max(1, Math.round(maxVol * MIN_TTS_VOLUME_FRACTION));
+        if (am.getStreamVolume(stream) < minVol) {
+            am.setStreamVolume(stream, minVol, 0);
+        }
+    } catch (Throwable th) {
+        Log.stack(LOG_ID, "ensureMinStreamVolume", th);
+    }
+}
+
 public void speak(String message) {
     if(!DontTalk) {
         try {
+            ensureMinStreamVolume();
             if(
                     ((android.os.Build.VERSION.SDK_INT >= 21)?
                     engine.speak(message, TextToSpeech.QUEUE_FLUSH, null,message):

Common/src/mobile/java/tk/glucodata/ui/alerts/CommonAlertSettings.kt

@@ -135,10 +135,10 @@ fun CommonAlertSettings(
                 unselectedContentColor = MaterialTheme.colorScheme.onPrimaryContainer
             )
 
-            AnimatedVisibility(visible = config.vibrationEnabled) {
+            AnimatedVisibility(visible = config.soundEnabled || config.vibrationEnabled) {
                 Column(verticalArrangement = Arrangement.spacedBy(6.dp)) {
                     Text(
-                        text = stringResource(R.string.haptics),
+                        text = stringResource(R.string.intensity),
                         style = MaterialTheme.typography.labelLarge,
                         color = MaterialTheme.colorScheme.onSurfaceVariant
                     )