Oh that is a much less clunky solution for handling the toggle effect! Will definitely have to borrow that as well.
Simpler question, how does one utilize the serialized contraptions like your paste?
If you copy the blob of text starting with "%%WGT0" and ending in the final "}" to your operating system's clipboard, and then within Decker choose "Edit -> Paste Widgets" (or "Edit -> Paste" in web-decker), the sample contraption instance along with its prototype will be added to the current card. If you already have a prototype with an identical name and a lower "version" number, the revised prototype will upgrade any existing contraption in place.
The "%%WGT0{...}" format is literally how widgets (and their dependencies; referenced fonts and prototypes) are represented in the system clipboard by Decker.