STACK MathQuill Editor

STACK Math Editor is a Moodle local plugin that adds a visual MathQuill-based formula editor to STACK question answer inputs in quiz attempts, quiz review, and STACK question preview contexts. The plugin injects a configurable toolbar for mathematical input, supports LaTeX-style entry, and converts the entered expressions into a form suitable for STACK / Maxima processing. It also provides instance-level defaults and per-question configuration for the available toolbar groups and variable handling.