fix: stop a queue drag from moving the wrong rows

A drop captured the dragged row's queue position once, at drag start, and
committed on a fire-and-forget coroutine. If the queue renumbered while the
drag was in flight (up-next consumed, a reconcile) or before a prior move had
reconciled, the drop resolved its target against stale coordinates and moved
the wrong entry - the "two middle rows swap on release" symptom.

Resolve the move from the current rows at drop time, and have move() report
whether it was accepted so a refused reorder is not announced as done; a
further move is refused while one is still committing.

app/src/test/kotlin/com/subtracks/ui/AppScreenshotTest.kt

@@ -506,7 +506,7 @@ class AppScreenshotTest {
                     onPlay = {},
                     onRemove = {},
                     onReorder = { _, _ -> },
-                    onMove = { _, _ -> },
+                    onMove = { _, _ -> true },
                     onLoadOlder = {},
                     onLoadNewer = {},
                     onUndo = {},

app/src/test/kotlin/com/subtracks/ui/playback/QueueViewModelTest.kt

@@ -325,6 +325,42 @@ class QueueViewModelTest {
         assertEquals((220L..399L).toList(), rowsSnapshot().map { it.position })
     }
 
+    @Test
+    fun ignoringASecondMoveWhileTheFirstIsStillCommitting() {
+        runBlocking { seedSongs(10) }
+        controller.playAlbum(1, "al1", 0)
+        await { controller.state.value.position == 0L }
+
+        viewModel.open()
+        await { viewModel.ready }
+        val before = rowsSnapshot().map { it.song.song.id }
+        val from = rowsSnapshot().first().position
+
+        runOnMain {
+            assertTrue(viewModel.move(from, from + 3))
+            assertFalse(viewModel.move(from, from + 1))
+        }
+
+        val expected = before.toMutableList().also { it.add(3, it.removeAt(0)) }
+        await { rowsSnapshot().map { it.song.song.id } == expected }
+        assertEquals(expected, rowsSnapshot().map { it.song.song.id })
+    }
+
+    @Test
+    fun dropMoveTakesTheDraggedRowsCurrentPosition() {
+        val rows =
+            listOf(
+                row(10).copy(id = 2L),
+                row(11).copy(id = 3L),
+                row(9).copy(id = 1L),
+            )
+
+        val move = rows.dropMoveFor(1L)!!
+
+        assertEquals(9L, move.from)
+        assertEquals(11L, move.to)
+    }
+
     @Test
     fun removingATrackUnderTheBlockReloadsRows() {
         runBlocking { seedSongs(10) }