* refactor(editor): split editor and watch surfaces
* fix(editor): revert behavior changes smuggled into the surface split
Restore merge-base React keys in IpynbCellOutputs: the content-identity keys
JSON.stringify'd every output value, including raw base64 image payloads, on
every keystroke.
Collapse the duplicated lazy() declarations into editor-lazy-views so each
viewer keeps a single React.lazy identity across the extracted surfaces.
Neil
e0bc4e1126