Adds user registration functionality and updates login logic in LoginPage.tsx. Replit-Commit-Author: Agent Replit-Commit-Session-Id: 556aa286-edd2-4cea-8583-f4fc3cfd119b Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/81470e0d-8ae8-4335-9301-cd9a69e670fa/96467e4f-00f2-4d88-82b1-142a9b24784c.jpg