Split undo redo fn from input (#78)

* implement copy/paste for wasm

* ignore wasm specific "dead" code

* fix ctrl instead of command on mac

* fix character input if clipboard shortcut held

* extract undo redo to own fn and refac

* fix first edit not being undoable

---------

Co-authored-by: StaffEngineer <111751109+StaffEngineer@users.noreply.github.com>