Build a console

This would help influence the overall design in a way that is future proof for the extensions system, scripting, and a headless or CLI version of the Graphite editor. Like in Blender, if you click a button to do something, it will be shown in the console (helpful for API discoverability) and you can also type your own commands.

No file, test, or entry point is named. Start by mapping the existing extensions, scripting, and headless/CLI architecture, then review how a Blender-style command console would fit the editor. Before implementation, define the console's scope and acceptance criteria for commands emitted by UI actions and user-entered commands.

Written by the indexing model from the issue text.