Present view options and search filters as popovers on macOS

Plain-Form sheets rendered as columns-style content floating inside
oversized fixed frames on macOS. Anchor these panels to their toolbar
buttons as popovers instead, sized to content; iOS/tvOS keep sheets.

- Search and PeerTube explore filters apply live (Cancel never
  reverted anything anyway) and dismiss on outside click
- Subscriptions/Manage Channels "Subscriptions Data" opens as a sheet
  from the popover's onDisappear via a pending flag, since presenting
  while the popover dismisses gets swallowed
- Media browser view options drop navigation chrome on macOS

Yattee/Views/MediaBrowser/MediaBrowserView.swift

@@ -59,6 +59,15 @@ struct MediaBrowserView: View {
         return sortedFiles(result)
     }
 
+    private var viewOptionsSheetContent: some View {
+        MediaBrowserViewOptionsSheet(
+            sourceType: source.type,
+            sortOrder: $sortOrder,
+            sortAscending: $sortAscending,
+            showOnlyPlayable: $showOnlyPlayable
+        )
+    }
+
     var body: some View {
         content
             #if !os(tvOS)
@@ -91,18 +100,20 @@ struct MediaBrowserView: View {
                         )
                     }
                     .liquidGlassTransitionSource(id: "mediaBrowserViewOptions", in: sheetTransition)
+                    #if os(macOS)
+                    .popover(isPresented: $showViewOptions, arrowEdge: .bottom) {
+                        viewOptionsSheetContent
+                    }
+                    #endif
                 }
                 #endif
             }
+            #if !os(macOS)
             .sheet(isPresented: $showViewOptions) {
-                MediaBrowserViewOptionsSheet(
-                    sourceType: source.type,
-                    sortOrder: $sortOrder,
-                    sortAscending: $sortAscending,
-                    showOnlyPlayable: $showOnlyPlayable
-                )
-                .liquidGlassSheetContent(sourceID: "mediaBrowserViewOptions", in: sheetTransition)
+                viewOptionsSheetContent
+                    .liquidGlassSheetContent(sourceID: "mediaBrowserViewOptions", in: sheetTransition)
             }
+            #endif
             .task {
                 await loadFiles()
             }

Yattee/Views/MediaBrowser/MediaBrowserViewOptionsSheet.swift

@@ -21,26 +21,43 @@ struct MediaBrowserViewOptionsSheet: View {
     }
 
     var body: some View {
+        #if os(macOS)
+        // Popover content: no navigation chrome, click-outside dismisses.
+        formContent
+            .padding()
+            .frame(width: 300)
+            .onAppear {
+                // Reset sort order if current selection is not available for this source type
+                if !availableSortOptions.contains(sortOrder) {
+                    sortOrder = .name
+                }
+            }
+        #else
         NavigationStack {
             #if os(tvOS)
             listContent
             #else
             formContent
+                .navigationTitle("mediaBrowser.viewOptions.title")
+                #if os(iOS)
+                .navigationBarTitleDisplayMode(.inline)
+                #endif
+                .toolbar {
+                    sheetCloseToolbarItem { dismiss() }
+                }
             #endif
         }
         #if os(iOS)
         .presentationDetents([.height(280)])
         .presentationDragIndicator(.visible)
         #endif
-        #if os(macOS)
-        .frame(minWidth: 420, minHeight: 320)
-        #endif
         .onAppear {
             // Reset sort order if current selection is not available for this source type
             if !availableSortOptions.contains(sortOrder) {
                 sortOrder = .name
             }
         }
+        #endif
     }
 
     @ViewBuilder
@@ -83,13 +100,6 @@ struct MediaBrowserViewOptionsSheet: View {
                 sharedOptions
             }
         }
-        .navigationTitle("mediaBrowser.viewOptions.title")
-        #if os(iOS)
-        .navigationBarTitleDisplayMode(.inline)
-        #endif
-        .toolbar {
-            sheetCloseToolbarItem { dismiss() }
-        }
     }
 }