[Pro] Submenus aren't reachable when Sidebar is in collapsible="icon" mode

[J4v4Scr1pt]

When Sidebar.Provider collapsible="icon" is in collapsed state, items with children
become inert — there's no way to expand a submenu or navigate to its children without
first expanding the whole sidebar back open.

Looking at the CSS, this seems intentional:

• .sidebar__menu-trigger { display: none } when collapsed
• Sidebar.Submenu only renders inline as expanded tree children — there's no
  out-of-flow surface for collapsed mode

For apps with grouped navigation (e.g. "Administration → Users / Teams / Segments"),
this means the entire group is unreachable in icon mode.

How are folks solving this today? Is the intended behavior that consumers shouldn't
put nested children under items they want reachable when collapsed, or is a
hover-popover style pattern (like shadcn/ui, Vercel, Linear) on the roadmap?

Happy to contribute a PR if there's a preferred direction.