fix(audio-rooms): DROP_OLDEST on the SubscribeHandle pump (audit #8)

The re-issuing pump's MutableSharedFlow used the default
onBufferOverflow = SUSPEND. A stalled consumer (decoder, player,
or anything downstream) back-pressured the pump → the inner
handle.objects.collect → the underlying transport → the relay.
Effect: the room caches up to 64 frames (~1.3s) on the consumer
side, then the relay slows down sending us audio.

For Opus audio the desired behavior is the inverse: drop OLD
frames so playback stays live after a UI hiccup or a foreground
transition. Switch to BufferOverflow.DROP_OLDEST so the relay
keeps streaming at full rate and the consumer's audio stays
synchronized with the speaker, at the cost of dropped frames
during stalls (which would have been late anyway).

nestsClient/src/commonMain/kotlin/com/vitorpamplona/nestsclient/ReconnectingNestsListener.kt

@@ -27,6 +27,7 @@ import com.vitorpamplona.nestsclient.transport.WebTransportFactory
 import com.vitorpamplona.quartz.nip01Core.signers.NostrSigner
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Job
+import kotlinx.coroutines.channels.BufferOverflow
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.MutableSharedFlow
@@ -250,7 +251,16 @@ private class ReconnectingHandle(
         activeListener.value
             ?: error("no live session — wait for state == Connected before subscribing")
 
-        val frames = MutableSharedFlow<MoqObject>(extraBufferCapacity = SUBSCRIBE_BUFFER)
+        // DROP_OLDEST so a stalled consumer doesn't back-pressure the
+        // pump → underlying handle → relay. For Opus audio the user
+        // wants playback to stay "live" rather than catch up on
+        // minutes-stale buffered frames after a UI hiccup or
+        // foreground/background transition.
+        val frames =
+            MutableSharedFlow<MoqObject>(
+                extraBufferCapacity = SUBSCRIBE_BUFFER,
+                onBufferOverflow = BufferOverflow.DROP_OLDEST,
+            )
         val liveHandleRef = AtomicReference<SubscribeHandle?>(null)
 
         // Re-subscribe pump: every time activeListener changes, drop