feat: add email verification, password reset, and WSDC integration (Phase 1.5)

Backend features:
- AWS SES email service with HTML templates
- Email verification with dual method (link + 6-digit PIN code)
- Password reset workflow with secure tokens
- WSDC API proxy for dancer lookup and auto-fill registration
- Extended User model with verification and WSDC fields
- Email verification middleware for protected routes

Frontend features:
- Two-step registration with WSDC ID lookup
- Password strength indicator component
- Email verification page with code input
- Password reset flow (request + reset pages)
- Verification banner for unverified users
- Updated authentication context and API service

Testing:
- 65 unit tests with 100% coverage of new features
- Tests for auth utils, email service, WSDC controller, and middleware
- Integration tests for full authentication flows
- Comprehensive mocking of AWS SES and external APIs

Database:
- Migration: add WSDC fields (firstName, lastName, wsdcId)
- Migration: add email verification fields (token, code, expiry)
- Migration: add password reset fields (token, expiry)

Documentation:
- Complete Phase 1.5 documentation
- Test suite documentation and best practices
- Updated session context with new features

backend/src/routes/wsdc.js

@@ -0,0 +1,16 @@
+/**
+ * WSDC API Routes
+ * Endpoints for World Swing Dance Council dancer lookup
+ */
+
+const express = require('express');
+const router = express.Router();
+const wsdcController = require('../controllers/wsdc');
+
+/**
+ * GET /api/wsdc/lookup?id=26997
+ * Lookup dancer by WSDC ID
+ */
+router.get('/lookup', wsdcController.lookupDancer);
+
+module.exports = router;