Remove dead code found by Periphery on all platforms

Delete declarations that Periphery reports unused on every platform that
compiles them (iOS, macOS, tvOS), including nine views used only by their
own previews. Platform-gated code still used on another platform, device-
only MPV render paths, migration models, CloudKit record names, App
Intents metadata and unused parameters are kept.

Yattee/Views/Components/BookmarkRowView.swift

@@ -13,8 +13,6 @@ import SwiftUI
 /// Automatically handles DeArrow integration.
 /// Supports optional queue context for auto-play functionality.
 struct BookmarkRowView: View {
-    @Environment(\.appEnvironment) private var appEnvironment
-
     let bookmark: Bookmark
     var style: VideoRowStyle = .regular
     var watchProgress: Double? = nil
@@ -27,10 +25,6 @@ struct BookmarkRowView: View {
     var videoIndex: Int? = nil
     var loadMoreVideos: LoadMoreVideosCallback? = nil
 
-    private var accentColor: Color {
-        appEnvironment?.settingsManager.resolvedAccentColor ?? .accentColor
-    }
-
     private var isBookmarkValid: Bool {
         bookmark.modelContext != nil && !bookmark.isDeleted
     }