fix(android): remove pollLoop natural-advance -- races with selectUpnp and skip

Polling alone cannot distinguish Sonos auto-advancing via SetNextAVTransportURI
from URI changes we made ourselves via syncCurrentItemToRemote.  This produced
two races: (1) activation race -- first poll returns stale URI from prior
session, second returns new URI, false-positive fires and double-advances the
cursor; (2) user-skip race -- skip's syncCurrentItemToRemote changes the URI,
next poll sees the change and fires again.  Remove the detection block and
previousTrackUri capture from pollOnce entirely.  pollLoop is now a pure
state-tracker (position + transport state) plus the one-shot initial pre-queue
gate.  GENA event subscriptions to AVTransport LastChange are the correct fix;
deferred to its own slice (see parity-map).

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

android/app/src/main/java/com/fabledsword/minstrel/player/MinstrelForwardingPlayer.kt

@@ -53,9 +53,9 @@ class MinstrelForwardingPlayer(
             holder.active.collect { active -> onActiveChanged(active) }
         }
         // No Player.Listener -- the seekToNextMediaItem/seekToPreviousMediaItem
-        // overrides and pollLoop natural-advance branch each call preQueueNext
-        // explicitly. A listener-based path raced with the override's launched
-        // syncCurrentItemToRemote, producing non-deterministic SOAP order.
+        // overrides call preQueueNext explicitly. A listener-based path raced
+        // with the override's launched syncCurrentItemToRemote, producing
+        // non-deterministic SOAP order.
     }
 
     private fun isRemote(): Boolean = holder.active.value != null
@@ -169,11 +169,9 @@ class MinstrelForwardingPlayer(
 
     /**
      * Speculative pre-queue of the next track so Sonos can advance gap-free.
-     * Failures (token mint OR SetNextAVTransportURI rejection) silently fall
-     * back to the poll-driven advance path -- the pollLoop detects STOPPED +
-     * 0:00 RelTime and calls syncCurrentItemToRemote on whatever the new
-     * currentMediaItem is. The only consequence of failure here is a sub-second
-     * audible gap at track boundary, not a broken route.
+     * Failures (token mint OR SetNextAVTransportURI rejection) are logged and
+     * swallowed. The only consequence is a sub-second audible gap at the track
+     * boundary, not a broken route.
      */
     private suspend fun preQueueNext(active: ActiveUpnp) {
         val nextMediaId = handlerEvaluate { nextItemMediaId() } ?: return
@@ -223,6 +221,15 @@ class MinstrelForwardingPlayer(
     }
 
     private suspend fun pollLoop(active: ActiveUpnp) {
+        // pollLoop is a state-tracker for position + transport state. We do NOT
+        // attempt to mirror Sonos's auto-advance into the local queue cursor --
+        // that would require GENA event subscriptions to AVTransport's LastChange
+        // event (see the parity-map). Without that, polling alone cannot
+        // distinguish "Sonos finished track N and auto-played track N+1 via
+        // SetNextAVTransportURI" from "we just changed Sonos's URI ourselves
+        // via syncCurrentItemToRemote". The local cursor stays in sync via user
+        // transport actions (pause/seek/skip flow through the override which
+        // re-runs syncCurrentItemToRemote).
         var initialPreQueueDone = false
         while (scope.isActive && holder.active.value?.routeId == active.routeId) {
             val outcome = runCatching { pollOnce(active) }
@@ -255,16 +262,11 @@ class MinstrelForwardingPlayer(
     }
 
     /**
-     * One poll tick: read position + transport state from Sonos, apply to
-     * [remoteState], and detect natural-advance (URI change driven by a
-     * previously queued SetNextAVTransportURI). Extracted from [pollLoop]
-     * to keep that method within detekt's LongMethod=60 limit.
+     * One poll tick: read position + transport state from Sonos and apply to
+     * [remoteState]. Extracted from [pollLoop] to keep that method within
+     * detekt's LongMethod=60 limit.
      */
     private suspend fun pollOnce(active: ActiveUpnp) {
-        // Capture before applyPositionInfo so we can detect a URI
-        // change that Sonos made via the pre-queued SetNextAVTransportURI
-        // (natural auto-advance without any user skip action).
-        val previousTrackUri = remoteState.currentTrackUri
         val info = active.avTransport.getPositionInfo()
         remoteState.applyPositionInfo(
             positionMs = info.relTimeMs,
@@ -278,28 +280,6 @@ class MinstrelForwardingPlayer(
             TransportState.STOPPED -> remoteState.applyTransportStopped()
             TransportState.TRANSITIONING, TransportState.UNKNOWN -> Unit
         }
-        // Detect remote-side natural advance: Sonos auto-advanced
-        // through SetNextAVTransportURI so the URI changed without
-        // any local user action. Advance the local queue cursor and
-        // call preQueueNext explicitly to set up the next-next URI on
-        // Sonos. Both guards must be non-blank: previousTrackUri="" on
-        // the very first poll and we must not treat that initial
-        // empty-to-URI transition as an advance.
-        if (info.trackUri.isNotBlank() &&
-            previousTrackUri.isNotBlank() &&
-            info.trackUri != previousTrackUri
-        ) {
-            Timber.w(
-                "UPnP natural-advance detected: %s -> %s",
-                previousTrackUri,
-                info.trackUri,
-            )
-            // Run on the application looper. ExoPlayer is paused
-            // while UPnP is active (playWhenReady=false invariant) so
-            // the cursor advances without producing local audio.
-            handler.post { delegate.seekToNextMediaItem() }
-            preQueueNext(active)
-        }
     }
 
     /** Run [block] on the application looper and bring its result back. */