feat: Enhance user authentication specifications and security measures

• Updated quickstart guide to include JWT (RS256) authentication and refresh token support.
• Revised research documentation to specify password storage and JWT token strategies.
• Modified specifications to clarify token expiration and security requirements.
• Added security checklist for user authentication, covering password safety, token management, and brute force protection.
• Created a comprehensive task list for implementing user authentication features, including registration, login, and security mechanisms.
• Introduced new markdown files for tracking recent activity and security requirements.