Password Security Vulnerability (Day 1-2)

- Plain text password storage with no security hashing
- Direct string comparison in authentication
- Credentials stored in localStorage with Missing password complexity validation

Start by locating the authentication code and every place credentials are stored or compared. The issue calls out plaintext passwords, direct string comparison, localStorage credentials, and missing complexity validation; done should mean these security problems are addressed and the authentication flow still works.

Written by the indexing model from the issue text.