feat(android): Auto-disable CA volume ducking when only one AirPod is worn (#616)

[QuantumBreakz]

Summary

Closes #616

Implements the app-side suppression approach suggested by @tabjy and accepted by @kavishdevar.

When the new "Only when both AirPods are worn" toggle is ON, the Conversational Awareness volume-ducking event (startSpeaking()) is silently ignored if fewer than two buds are currently in-ear. The stopSpeaking() (volume restore) path is never gated, so volume can never get stuck low.

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Changes

AirPodsService.kt

• Added conversationalAwarenessBothPodsOnly: Boolean = false to ServiceConfig
• Seeded conversational_awareness_both_pods_only in first-run SharedPreferences defaults (false)
• Loaded the pref in initializeConfig()
• Added live-change case in onSharedPreferenceChanged()
• The gate in onConversationAwarenessReceived():

  val budsInEar = earDetectionNotification.status.count { it == 0x00.toByte() }
  val blockedForSinglePod = config.conversationalAwarenessBothPodsOnly && budsInEar < 2
  if (status == 1 || status == 2) {
      if (!blockedForSinglePod) MediaController.startSpeaking()
  } else if (status == 6 || 8 || 9) {
      MediaController.stopSpeaking() // never gated
  }

AppSettingsViewModel.kt

• Added conversationalAwarenessBothPodsOnlyEnabled: Boolean = false to AppSettingsUiState
• Loaded the pref in loadSettings()
• Added setConversationalAwarenessBothPodsOnlyEnabled(enabled: Boolean) setter

AppSettingsScreen.kt

• Added a third StyledToggle inside the existing Conversational Awareness StyledList, between "Pause Music" and "Relative volume"

strings.xml

<string name="conversational_awareness_both_pods_only">Only when both AirPods are worn</string>
<string name="conversational_awareness_both_pods_only_description">Only lowers the volume when you speak if both AirPods are in your ears.</string>

---

Behaviour

Toggle	One AirPod	Both AirPods
OFF (default)	Volume ducks ✅	Volume ducks ✅
ON	Volume does not duck ✅	Volume ducks ✅

The stopSpeaking() path always runs regardless of toggle state — volume is always restored.

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Testing

Build verified: ./gradlew assembleFossDebug → BUILD SUCCESSFUL (51 tasks, 0 errors).

Manual test steps:

1. Enable the toggle in Settings → Conversational Awareness
2. Play music, insert one AirPod, speak → volume should not duck
3. Insert both AirPods, speak → volume should duck
4. Disable the toggle → always ducks (original behaviour restored)

---

Notes

• Default is false in all five required places — zero behaviour change for existing users
• Uses app-side suppression (no firmware commands) as recommended by the reporter
• Reads ear state from the existing earDetectionNotification.status array (0x00 = in-ear)

[QuantumBreakz]

Hey @kavishdevar 👋

This PR implements the feature requested in #616 by @tabjy using the app-side suppression approach you approved.

Since this is submitted from a fork, I can't set reviewers or assignees programmatically. Could you please:

• Assign yourself (or another maintainer) as reviewer
• Assign @tabjy as the original reporter/assignee if appropriate

Build is verified: ./gradlew assembleFossDebug → BUILD SUCCESSFUL (51 tasks, 0 errors, 0 new warnings).

Happy to make any changes based on your review! 🙏