Text labels

Some mobile editors allow putting text pictures. It can be just text or embedded in some bubble for better look.

For this we need a button which creates a bubble and editable text inside. Would be great to be able to change shape and color of the bubble, or just disable the bubble and leave only plain text.

No files, tests, or entry points are named. Start by locating the mobile editor's existing controls and image-editing model, then clarify the scope for creating editable text and an optional bubble. Done should cover text insertion plus the agreed bubble shape, color, and disable options.

Written by the indexing model from the issue text.