UI state and access refinement (OTP, navigation, error handling)

[Vikasredz]

This pull request includes improvements related to UI state handling, access control, and frontend behaviour consistency across multiple screens in the Guardian Monitor application.

🔧 Key Changes
Error State Handling

• Fixed incorrect error message during duplicate email registration.
• Previously, the system displayed a raw or unclear string.
• Now shows a clear and user-friendly message: “Email already taken”.

Incomplete Frontend Behaviour**

• Improved OTP input experience by implementing automatic focus transition between input fields.
• Eliminates the need for manual navigation, improving usability.

UI State Improvements

• Investigated and partially implemented dark mode.
• Identified readability and contrast issues, which are noted for further refinement.

Action Visibility & Navigation Fixes

• Fixed menu button functionality in:
• Edit Caretaker Profile screen
• Caretaker Profile screen
• Connected menu button properly to the drawer layout to ensure correct navigation behaviour.

Access & Navigation Enhancement

• Resolved a major issue in the Training screen where users had no navigation options.
• Added menu access (drawer navigation), ensuring users are not stuck on the screen.
• Improved consistency with other screens in the application.