[Mothra-Neon UI request] When Neon first opens, make the default Edit rather than Insert

I could probably have found a better title for this, but anyway, here's the situation:

When a user first gets to Neon, the right-hand panel is set on Insert. So if the user clicks on the page, a punctum appears! This is befuddling. Could the panel be set on Edit instead? I believe standalone Neon has the Syllable selection mode selected when the page first opens, so Mothra-Neon could do the same.

Inspect the Neon UI initialization and the existing standalone Neon startup behavior, especially where the right-hand panel mode is selected. Change the initial Mothra-Neon mode to Edit or Syllable selection rather than Insert, then verify that clicking the page on first open does not create a punctum.

Written by the indexing model from the issue text.