bug: Long-term mentee registration Submit silently does nothing when availableHsMonth is invalid

[yingliu-data]

Bug Report

For long-term cycles, the mentee-registration Submit button can silently do nothing: the form fails validation on a field that is not shown on the final step, so no error is displayed.

• src/schemas/menteeSchema.ts (superRefine) requires availableHsMonth >= 2 for LONG_TERM (and >= 1 for AD_HOC); the default value is 0.
• src/pages/mentorship/mentee-registration.tsx — validateStep1 (the step-1 trigger([...]) list) does not include availableHsMonth, yet the field is rendered on step 1. The final submit uses handleSubmit(onSubmit) with no onInvalid handler.

Reproduction (when IS_ADHOC_CYCLE=false)

1. User leaves "Available hours per month" at its default 0 (or enters 1).
2. Step 1 passes because availableHsMonth is not in the step-1 trigger list.
3. User reaches the final step and clicks Submit.
4. The resolver fails on availableHsMonth, whose input lives on step 1, so no error renders anywhere — the button appears dead and nothing happens.

Currently dormant because IS_ADHOC_CYCLE=true, but it will affect every long-term cycle.

Severity

High (dormant today; breaks every long-term cycle when ad-hoc mode is off)

Potential Risk

• Mentees silently unable to submit long-term applications, with no visible reason.

Suggested Fix

• Add availableHsMonth to the step-1 trigger list so it is validated on the step where it is rendered and the error is shown in context.
• Add an onInvalid handler to handleSubmit that surfaces validation errors (e.g. focuses/scrolls to the first invalid field or shows a summary) so a failed submit is never silent.
• Add a test covering long-term submission with availableHsMonth below the threshold (expect a visible validation error, not a no-op).