Present shared sheets through one host per window

The add-to-playlist, download options and queue sheets were declared in
every view that could open them: the root view (twice, mirrored from
coordinator flags), the expanded player, its portrait and floating
panels, the player controls and the video info view.

AppSheet lists the shared sheets, and .appSheetHost() declares them
once. The app root and the expanded player each host them, and every
presented sheet hosts the next level. Views present through the
presentAppSheet environment action, which reaches the nearest host;
code without a view (and the expanded player itself, whose host sits
in its own body) uses PresentationRouter.request, taken by the
top-most host: the player while it is up, the root otherwise.

The mini player's queue and playlist sheets now go through the host,
replacing the isMiniPlayer*SheetPresented flags.

Yattee/Views/Player/ExpandedPlayerSheet.swift

@@ -18,10 +18,7 @@ struct ExpandedPlayerSheet: View {
     // MARK: - Sheet State
 
     @State var showingQualitySheet = false
-    @State var showingPlaylistSheet = false
-    @State var showingDownloadSheet = false
     @State var showingDeleteDownloadAlert = false
-    @State var showingQueueSheet = false
     @State var showingErrorSheet = false
     @State var isCommentsExpanded: Bool = false
     @State var commentsDismissOffset: CGFloat = 0
@@ -178,14 +175,38 @@ struct ExpandedPlayerSheet: View {
         )
     }
 
+    // MARK: - Shared Sheets
+
+    /// Presents through the player's sheet host. The host sits inside this
+    /// view's body, so this view's own environment can't reach it; the global
+    /// request does, because the player host takes requests while it is up.
+    func presentSheet(_ sheet: AppSheet) {
+        appEnvironment?.navigationCoordinator.presenter.present(sheet)
+    }
+
+    func presentAddToPlaylist() {
+        guard let video = playerState?.currentVideo else { return }
+        presentSheet(.addToPlaylist(video))
+    }
+
+    #if !os(tvOS)
+    func presentDownloadOptions() {
+        guard let video = playerState?.currentVideo, let playerService = appEnvironment?.playerService else { return }
+        presentSheet(.downloadOptions(
+            video,
+            streams: playerService.availableStreams,
+            captions: playerService.availableCaptions,
+            dislikeCount: playerState?.dislikeCount
+        ))
+    }
+    #endif
+
     // MARK: - Body
 
     var body: some View {
         playerContentWithOverlays
             .applyPlayerSheets(
                 showingQualitySheet: $showingQualitySheet,
-                showingPlaylistSheet: $showingPlaylistSheet,
-                showingDownloadSheet: $showingDownloadSheet,
                 showingDeleteDownloadAlert: $showingDeleteDownloadAlert,
                 onStreamSelected: { stream, audioStream in
                     switchToStream(stream, audioStream: audioStream)
@@ -469,9 +490,6 @@ struct ExpandedPlayerSheet: View {
             }
         }
         .animation(.spring(response: 0.3, dampingFraction: 0.7), value: commentsState == .loaded && !comments.isEmpty)
-        .sheet(isPresented: $showingQueueSheet) {
-            QueueManagementSheet()
-        }
         .sheet(isPresented: $showingErrorSheet) {
             ErrorDetailsSheet(errorMessage: playerState?.errorMessage ?? "Unknown error")
         }
@@ -495,6 +513,9 @@ struct ExpandedPlayerSheet: View {
             shouldHost: (appEnvironment?.navigationCoordinator.isPlayerExpanded == true),
             appEnvironment: appEnvironment
         )
+        // Shared sheets opened from the player, and global requests while it
+        // is up, so they appear above the player window.
+        .appSheetHost(isTopLevel: appEnvironment?.navigationCoordinator.isPlayerExpanded == true)
         #if os(iOS)
         .toolbar(.hidden, for: .navigationBar)
         // Corner layout with panels visible keeps the system status bar and
@@ -516,15 +537,11 @@ private extension View {
     @ViewBuilder
     func applyPlayerSheets(
         showingQualitySheet: Binding<Bool>,
-        showingPlaylistSheet: Binding<Bool>,
-        showingDownloadSheet: Binding<Bool>,
         showingDeleteDownloadAlert: Binding<Bool>,
         onStreamSelected: @escaping (Stream, Stream?) -> Void
     ) -> some View {
         modifier(PlayerSheetsModifier(
             showingQualitySheet: showingQualitySheet,
-            showingPlaylistSheet: showingPlaylistSheet,
-            showingDownloadSheet: showingDownloadSheet,
             showingDeleteDownloadAlert: showingDeleteDownloadAlert,
             onStreamSelected: onStreamSelected
         ))
@@ -535,8 +552,6 @@ private extension View {
 private struct PlayerSheetsModifier: ViewModifier {
     @Environment(\.appEnvironment) var appEnvironment
     @Binding var showingQualitySheet: Bool
-    @Binding var showingPlaylistSheet: Bool
-    @Binding var showingDownloadSheet: Bool
     @Binding var showingDeleteDownloadAlert: Bool
     let onStreamSelected: (Stream, Stream?) -> Void
 
@@ -549,15 +564,7 @@ private struct PlayerSheetsModifier: ViewModifier {
             .sheet(isPresented: $showingQualitySheet) {
                 qualitySelectorSheet
             }
-            .sheet(isPresented: $showingPlaylistSheet) {
-                if let video = playerState?.currentVideo {
-                    PlaylistSelectorSheet(video: video)
-                }
-            }
             #if !os(tvOS)
-            .sheet(isPresented: $showingDownloadSheet) {
-                downloadSheet
-            }
             .alert(
                 String(localized: "player.deleteDownload.title"),
                 isPresented: $showingDeleteDownloadAlert
@@ -648,19 +655,6 @@ private struct PlayerSheetsModifier: ViewModifier {
         }
     }
 
-    #if !os(tvOS)
-    @ViewBuilder
-    private var downloadSheet: some View {
-        if let video = playerState?.currentVideo, let playerService {
-            DownloadQualitySheet(
-                video: video,
-                streams: playerService.availableStreams,
-                captions: playerService.availableCaptions,
-                dislikeCount: playerState?.dislikeCount
-            )
-        }
-    }
-    #endif
 }
 
 // MARK: - Player Event Handlers Modifier