feat: enhance background streaming functionality with improved wake lock management

- Updated the wake lock duration in BackgroundStreamingHandler to 3 hours, ensuring the service remains active for longer periods.
- Modified the keepAlive method to support both iOS and Android, allowing for better background task management across platforms.
- Implemented a periodic keep-alive timer in VoiceCallService to refresh the wake lock every 5 minutes, enhancing service reliability during voice calls.
- Added debug logging for successful keep-alive invocations, improving traceability of background operations.

android/app/src/main/kotlin/app/cogwheel/conduit/BackgroundStreamingHandler.kt

@@ -144,13 +144,13 @@ class BackgroundStreamingService : Service() {
     
     private fun acquireWakeLock() {
         if (wakeLock?.isHeld == true) return
-        
+
         val powerManager = getSystemService(Context.POWER_SERVICE) as PowerManager
         wakeLock = powerManager.newWakeLock(
             PowerManager.PARTIAL_WAKE_LOCK,
             "Conduit::StreamingWakeLock"
         ).apply {
-            acquire(15 * 60 * 1000L) // 15 minutes max
+            acquire(3 * 60 * 60 * 1000L) // 3 hours max (refreshed every 5 minutes)
         }
         println("BackgroundStreamingService: Wake lock acquired")
     }