iOS: stem playlist refresh and covers, download queue page, reorderable Library, whole-library radio

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

ios/Stemify/UI/Components/MediaMenu.swift

@@ -15,7 +15,14 @@ struct MediaMenu {
             a.append(SheetAction("Remove Download", icon: "trash", destructive: true) { g.downloads.remove([t]) })
         }
         a.append(SheetAction("Add to Playlist…", icon: "text.badge.plus") { addToPlaylist([t]) })
-        if t.partFile != nil, g.stems.index.size > 0, g.stems.find(t) == nil { a.append(stemNow { [t] }) }
+        if t.partFile != nil, g.stems.index.size > 0, g.stems.find(t) == nil {
+            let s = g.stems.state(t)
+            if s == .stemming || s == .queued {
+                a.append(SheetAction(s == .stemming ? "Stemming…" : "Queued for Stems", icon: "waveform") {})
+            } else {
+                a.append(stemNow { [t] })
+            }
+        }
         if allowGoTo, let k = t.albumKey {
             a.append(SheetAction("Go to Album", icon: "square.stack") {
                 ui.showInLibrary(.AlbumPage(Album(ratingKey: k, title: t.album, artist: t.artist, artistKey: t.artistKey, year: t.year, thumb: t.thumb)))
@@ -68,6 +75,17 @@ struct MediaMenu {
                                 { pl.tracks }, confirm: false))
         if pl.items.isEmpty { a = [] }
         let lists = g.stemPlaylists
+        if !pl.items.isEmpty {
+            a.append(SheetAction("Change Cover…", icon: "photo") {
+                var seen = Set<String>()
+                var acts: [SheetAction] = [SheetAction("Automatic", icon: "wand.and.stars") { lists.setArt(pl.id, nil) }]
+                for t in pl.tracks {
+                    guard let th = t.thumb, seen.insert(th).inserted, seen.count <= 20 else { continue }
+                    acts.append(SheetAction(t.album, icon: th == pl.artThumb ? "checkmark" : "photo") { lists.setArt(pl.id, th) })
+                }
+                overlays.actions("Choose a Cover", acts)
+            })
+        }
         a.append(SheetAction("Delete Stem Playlist", icon: "trash", destructive: true) {
             overlays.confirm("Delete “\(pl.title)”?", "Stem playlists are only on this device.", "Delete") { lists.delete(pl.id); if onPage { ui.pop() } }
         })