The desktop text selection toolbars, as introduced in #73882 and #74286, have major limitations that make them not as good as native. We should either find a way to use the native context menus, or we should work to fix each of these problems.

• We can't draw the menu outside of the current window. Also, the menu can't receive mouse events (like hover) unless the current menu is focused.
• The only buttons available are the default mobile buttons (cut/copy/paste/select all). We should support all of the same buttons that display natively.
• It should be possible for Flutter devs to customize the menu.
• The native Mac menu has a flashing animation when clicked.
• Submenus should be possible and easy to implement.
• Currently, only EditableText widgets can show the menu. Right-clicking elsewhere doesn't show it. Fixing this probably requires refactoring TextSelectionControls to work with both the existing setup and menus (like showMenu).
• Menu items that are wider than the default width are ellided, but on native the menu grows to accommodate them.
• On Windows and Linux we use a Material-style menu, but we might want to build a menu that looks like the native one instead.
• The native Mac context menu is slightly transparent and has a blur effect (screenshots below).