New: tell us about your accessibility needs during sign-up

Signing up now includes one new, optional question on the "Tell Us About You" step: anything we should know to make mentorship or feedback more accessible for you -- captioning, screen-reader compatibility, session pacing, preferred communication style, or anything else. Free text, nothing required, and it never blocks you from finishing sign-up.

This is a first step, not a finished system -- nothing in this app automatically acts on what you write here yet. We wanted the option to exist and be asked honestly before building anything more on top of it.