fix(android): effectiveDuration uses desiredIdx so duration tracks the displayed title

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

@@ -462,6 +462,8 @@ class PlayerController @Inject constructor(
                                 upnpActive,
                                 remoteState.durationMs,
                                 player.duration,
+                                desiredIdx = idx,
+                                controllerIdx = idx,
                             ),
                             bufferedPositionMs = player.bufferedPosition.coerceAtLeast(0),
                             playbackError = player.playerError?.message,
@@ -525,7 +527,13 @@ class PlayerController @Inject constructor(
         val desiredIdx = desiredQueueIndex(controller, upnpActive)
         val current = uiStateInternal.value
         val newPos = effectivePosition.coerceAtLeast(0)
-        val newDur = effectiveDuration(upnpActive, remoteState.durationMs, controller.duration)
+        val newDur = effectiveDuration(
+            upnpActive,
+            remoteState.durationMs,
+            controller.duration,
+            desiredIdx = desiredIdx,
+            controllerIdx = controller.currentMediaItemIndex,
+        )
         val newBuf = controller.bufferedPosition.coerceAtLeast(0)
         // Track adjustments are forward-only AND suppressed while a user
         // transport press is pending Sonos confirmation. Together those keep
@@ -691,11 +699,22 @@ class PlayerController @Inject constructor(
      * until the first SOAP poll lands.
      */
     @Suppress("ReturnCount") // 3-tier fallback reads cleanest as a ladder of early returns
-    private fun effectiveDuration(upnpActive: Boolean, remoteMs: Long, localMs: Long): Long {
+    private fun effectiveDuration(
+        upnpActive: Boolean,
+        remoteMs: Long,
+        localMs: Long,
+        desiredIdx: Int,
+        controllerIdx: Int,
+    ): Long {
         if (upnpActive && remoteMs > 0) return remoteMs
-        if (localMs > 0) return localMs
-        val idx = mediaController?.currentMediaItemIndex ?: 0
-        val ref = queueRefs.getOrNull(idx) ?: return 0
+        // Tier 2 (wrapped player's probed duration) only valid when the
+        // wrapped player is on the same track we're trying to show. After a
+        // Sonos natural advance the polling tick updates desiredIdx from
+        // Sonos's truth while controllerIdx is briefly stale -- using the
+        // wrapped player's duration here would surface the old track's
+        // length under the new track's title.
+        if (localMs > 0 && controllerIdx == desiredIdx) return localMs
+        val ref = queueRefs.getOrNull(desiredIdx) ?: return 0
         return ref.durationSec.toLong() * MS_PER_SECOND
     }