Fixed missing keyboard and screen-reader labels across sign-up, critique, and Skill Labs

We reviewed keyboard-only and screen-reader use across account creation, search, critique, booking, learning, and job applications against WCAG 1.3.1 and 4.1.2 -- checking the real markup, not assuming it was already fine.

Real gaps, now fixed: every field on both Critique forms (the full submission form and the response form) had a visible label that was never actually linked to its input, so a screen reader announced nothing useful for it. Account creation had the same gap on every auth field. On Jobs, the title and location filters had only a nearby heading, not a real label, and two fields on the job tracker (next action, private notes) had only placeholder text. Skill Labs' workspace had three unlabeled fields, including its own AI-disclosure field.

Booking was already done right -- we checked it as a comparison point and made no changes there. That was a useful signal that this gap traces to forms built before we started holding new work to this standard, not something that runs through the whole app.