fix the startup reveal and the first-play hitch for real

The mini player's enter spec was decided from `firstReveal`, which was false at the first
composition (the player is not visible yet) and flipped back to `expandVertically` in the
same frame the visibility changed, so the expand animation always ran. PlaybackState now
carries `restored`, set by restore() and cleared on any user playback, and the mini
player uses it to appear in place for the whole restored session.

The first play after a restart could still pay for a fresh buffer because a stream-quality
reload rebuilds the window, and loadWindow only prepared when autoplay was set. It now
always prepares, so a reload (or the restore) leaves the current track buffered.

app/src/main/kotlin/com/subtracks/playback/PlaybackController.kt

@@ -52,6 +52,7 @@ data class PlaybackState(
     val hasPrevious: Boolean = false,
     val shuffle: Boolean = false,
     val repeat: RepeatMode = RepeatMode.Off,
+    val restored: Boolean = false,
 )
 
 private sealed interface QueueUndo {
@@ -127,6 +128,7 @@ class PlaybackController(
     private var repeatMode = RepeatMode.Off
     private var endedHandled = false
     private var lastSavedPositionMs = 0L
+    private var restored = false
 
     init {
         scope.launch {
@@ -226,6 +228,7 @@ class PlaybackController(
             windowEnd = -1
             lastEdit = null
             endedHandled = false
+            restored = false
             val previous = snapshot
             val previousEntry = previous?.entries?.firstOrNull()?.entry
             val same = previousEntry != null && previousEntry.kind == entry.kind && previousEntry.refId == entry.refId
@@ -601,6 +604,7 @@ class PlaybackController(
         windowEnd = -1
         lastEdit = null
         endedHandled = false
+        restored = false
         val modes = queueRepository.modes()
         shuffleEnabled = !disableShuffle && modes.shuffle
         repeatMode = modes.repeat.toRepeatMode()
@@ -661,8 +665,8 @@ class PlaybackController(
             this.queueSourceId = queueSourceId
             val position = queueRepository.cursor().coerceIn(0, snapshot.size - 1)
             lastSavedPositionMs = queueRepository.cursorPositionMs().coerceAtLeast(0)
+            restored = true
             loadWindow(position, autoplay = false, startPositionMs = lastSavedPositionMs)
-            player?.prepare()
         }
 
     private suspend fun stop() = startLock.withLock { stopLocked() }
@@ -677,6 +681,7 @@ class PlaybackController(
         windowStart = 0
         windowEnd = -1
         lastEdit = null
+        restored = false
         player?.run {
             stop()
             clear()
@@ -701,10 +706,8 @@ class PlaybackController(
         updating = true
         player.setWindow(window.map { it.item.toQueueItem() }, startIndex, startPositionMs)
         updating = false
-        if (autoplay) {
-            player.prepare()
-            player.play()
-        }
+        player.prepare()
+        if (autoplay) player.play()
         refresh(position)
     }
 
@@ -940,6 +943,7 @@ class PlaybackController(
                 hasPrevious = true,
                 shuffle = shuffleEnabled,
                 repeat = repeatMode,
+                restored = restored,
             )
         if (player.isPlaying) startPositionTicker() else stopPositionTicker()
     }

app/src/main/kotlin/com/subtracks/ui/AppRoot.kt

@@ -5,6 +5,7 @@ import androidx.activity.OnBackPressedCallback
 import androidx.activity.compose.LocalOnBackPressedDispatcherOwner
 import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.animation.EnterTransition
+import androidx.compose.animation.ExitTransition
 import androidx.compose.animation.core.animate
 import androidx.compose.animation.core.animateDpAsState
 import androidx.compose.animation.core.snap
@@ -233,12 +234,9 @@ private fun MainNavigation() {
     val navBarInset = with(density) { WindowInsets.navigationBars.getBottom(this).toDp() }
     val keyboardUp = WindowInsets.imeAnimationTarget.getBottom(density) > 0
     val showMiniPlayer = playerVisible && !keyboardUp
-    var miniPlayerRevealed by remember { mutableStateOf(false) }
-    val firstReveal = !miniPlayerRevealed && showMiniPlayer
-    LaunchedEffect(showMiniPlayer) { if (showMiniPlayer) miniPlayerRevealed = true }
     val bottomInset by animateDpAsState(
         targetValue = if (showMiniPlayer) 0.dp else navBarInset,
-        animationSpec = if (firstReveal) snap() else tween(MINI_PLAYER_ANIM_MS),
+        animationSpec = if (playback.restored) snap() else tween(MINI_PLAYER_ANIM_MS),
         label = "libraryBottomInset",
     )
 
@@ -382,12 +380,17 @@ private fun MainNavigation() {
                 AnimatedVisibility(
                     visible = showMiniPlayer,
                     enter =
-                        if (firstReveal) {
+                        if (playback.restored) {
                             EnterTransition.None
                         } else {
                             expandVertically(tween(MINI_PLAYER_ANIM_MS), expandFrom = Alignment.Bottom)
                         },
-                    exit = shrinkVertically(tween(MINI_PLAYER_ANIM_MS), shrinkTowards = Alignment.Bottom),
+                    exit =
+                        if (playback.restored) {
+                            ExitTransition.None
+                        } else {
+                            shrinkVertically(tween(MINI_PLAYER_ANIM_MS), shrinkTowards = Alignment.Bottom)
+                        },
                 ) {
                     val positionMs by playbackController.positionMs.collectAsStateWithLifecycle()
                     val miniArt = playbackController.coverArt(playback.item, thumbnail = true)

app/src/test/kotlin/com/subtracks/playback/PlaybackControllerTest.kt

@@ -160,6 +160,20 @@ class PlaybackControllerTest {
         assertEquals(listOf("play"), handle.operations)
     }
 
+    @Test
+    fun restoringMarksTheStateUntilPlaybackStarts() {
+        seedAlbum(5, sourceId = 1)
+        runBlocking { queues.replace(listOf(queues.albumEntry(1, "al1"))) }
+
+        controller.connect()
+        await { handle.items.isNotEmpty() }
+
+        assertTrue(controller.state.value.restored)
+
+        controller.playAlbum(1, "al1", 0)
+        await { !controller.state.value.restored }
+    }
+
     @Test
     fun nextAdvancesTheCursor() {
         seedAlbum(3, sourceId = 1)
@@ -1067,7 +1081,9 @@ class PlaybackControllerTest {
 
         assertEquals(33_000L, handle.positionMs)
         assertFalse(handle.playWhenReady)
-        assertTrue(handle.operations.drop(before).none { it.startsWith("prepare") || it.startsWith("play") })
+        val reload = handle.operations.drop(before)
+        assertTrue("a reload must re-prepare, or the next play pays for it", reload.any { it == "prepare" })
+        assertTrue(reload.none { it == "play" })
     }
 
     @Test