* Add simple mask editor add-on API
* Signal completed mask editor image loading to Python
* Add API methods for querying mask editor state, fix formatting
* Use event forwarding to propagate image loaded event
Should fix mobile support by moving all bridgeCommand calls to `NoteEditor.svelte`
* Add shape classes to mask editor API
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Co-authored-by: Glutanimate <glutanimate@users.noreply.github.com>