- Add database migration for candidate_profiles, candidate_interviews,
and candidate_offers tables with RLS policies
- Add API endpoints: /api/candidate/profile, /api/candidate/interviews,
/api/candidate/offers
- Add CandidatePortal.tsx main dashboard with stats, quick actions,
upcoming interviews, and pending offers
- Add CandidateProfile.tsx profile builder with tabs for basic info,
work experience, education, and portfolio links
