feat: workshop form, admin dashboard, Tailwind migration & new features

[techymualim]

Summary

Major update covering workshop registration form improvements, admin dashboard enhancements, UI migration to Tailwind CSS, and several new backend/frontend features.

Workshop Form

• Removed slider component
• Separate LinkedIn (mandatory) and GitHub (optional) fields
• Phone number regex validation (supports formats like +92 300 1234567)
• Added Gender field (Male, Female, Non-Binary, Prefer not to say)
• Added "What defines you best" field (Student, Young Professional, Intermediate Expert, Senior Expert, Freelancer, Other)
• Registration now defaults to pending status (not confirmed)

Admin Dashboard - Registration Management

• Search/filter by CNIC, Email, Name, Status, Phone Number, "Defines you best"
• Status flow: pending → shortlisted (email + QR ticket) → attended (QR scan)
• Rejection flow: pending → rejected (rejection email sent)
• QR code generated on shortlist with participant name, email, phone, CNIC
• QR Scanner page with camera support + manual input, shows participant info popup
• Pagination on Users, Registrations, and Workshops tables

Email System

• Pending registration confirmation email
• Shortlisted email with QR code ticket and event details
• Attended confirmation email on check-in
• Rejection notification email
• Batch email sending (100 emails per batch)

New Modules

• Users CRUD module (add/update/delete system admin users) - frontend + backend
• QR Scan admin page for scanning participant tickets
• Swagger UI at /api/docs for API documentation

Infrastructure

• Rate limiting (30 req/min via @nestjs/throttler)
• CORS policy with allowed methods/headers
• Tailwind CSS migration - entire frontend UI migrated from vanilla CSS to Tailwind

Test plan

• Register for a workshop and verify pending status + pending email
• Admin shortlists a registration → verify shortlisted email with QR code
• Scan QR code on admin QR Scan page → verify participant info popup
• Mark as attended from QR scan → verify attended email
• Reject a registration → verify rejection email
• Test search/filter on registrations (by CNIC, email, name, status, phone, profile type)
• Test pagination on registrations, workshops, and users tables
• Create/update/delete admin users in Users module
• Verify phone number regex rejects invalid formats
• Verify LinkedIn field is mandatory, GitHub is optional
• Verify Swagger UI loads at /api/docs
• Verify rate limiting blocks excessive requests
• Test CSV export with new fields (gender, defines_you_best, separate github/linkedin)

https://claude.ai/code/session_019HaZFm7kRZ75LduVPF4qrA