Feature Request: Make Quick Bar a dockable, movable pane with tree structure support

## Background
I have many quick commands in the Quick Bar.
It is fixed at the bottom and cannot be moved, resized, or grouped in a tree structure, which is very inconvenient to use.
Also, when a quick command contains multiple commands, I need to set a delay interval between them.

## Request
1. Make the Quick Bar a dockable, movable, resizable panel like other panes.
2. Support tree / folder structure to organize commands.
3. Support setting delay intervals between multiple commands in one quick action.
4. Keep all existing functions.

## Benefits
- More flexible layout
- Easier to manage a large number of commands
- More stable when executing multiple commands in sequence

Thank you for your great work!

Start by locating the Quick Bar implementation and the existing pane and quick-command behavior. Review how commands are organized and executed, then determine the scope needed for movable, resizable docking, tree structures, and per-command delays. Done means all four requested capabilities work while existing Quick Bar functions remain intact.

Written by the indexing model from the issue text.