[Feature Request] Tab trees in vertical tabs list

[wiggleforlife]

Is your feature request related to a problem?

I find tab trees very helpful for my organisation - having over two hundred tabs makes finding tabs difficult without groups.

Describe the solution you'd like

I'd like the implementation of this to be similar to Sidebery's, as this is what I currently use, but I understand if there has to be differences.
Tab trees are different from Floorp's Workspaces because they are smaller groups inside of a Workspace.

• You can fold a tree by clicking on the parent tab's icon and create a tree by dragging and dropping a tab onto another.
• Trees can also be created by opening a link in a new tab - the original tab is the parent tab and the new tab becomes a child tab.
• Trees can be inside of other trees

Describe alternatives you've considered

No response

Additional context

A tree with more trees as children.

A folded tree.

The arrow that appears to indicate a tab tree being created while dragging and dropping.

Love what you're doing with this browser, especially since it's using Gecko and Firefox instead of Chromium!! Thank you!!