Scintilla, the editing widget Geany uses offers wrapping options of:
1. off 2. between runs of the same style 3. between any two characters (your request), and 4. at whitespace
Currently Geany only allows a boolean selection between 1. and 2. per file and a global default when files are newly opened.
Somebody will need to provide a PR to provide UI for choosing other options, applying, and saving and restoring the choice (remembering its per file, not global) and also a global default for newly opened files and apply, save and restore of that.