All always-on tools, in registration order.
Disengage the hotkey-slot tool, if any.
Engage a hotkey-slot tool by id.
Currently hotkey-engaged tool id (or null). Derived as the top of
the hotkey stack for backwards compat with the pre-stack API.
Full registry — for userland UI (palette buttons, etc.).
Set the active-slot tool. The gesture dispatcher watches the active tool and cancels any in-flight handle itself.
All overlay layers from currently-engaged tools (active slot, hotkey
slot if engaged, all ambient slot tools). Filters out tools with no
overlay field. Order: active, then hotkey (if engaged), then
ambient (registration order).
Returns true if a tool with the given id is in the registry or ambient list.
Current active-slot tool id.