Refactor Error Handling and Imports in Authentication Logic

[0010aor]

Description

Improve the authentication logic in the frontend by standardizing error handling and updating import paths for consistency and maintainability.

Current Behavior

• The useAuth hook currently handles errors with a verbose and inconsistent pattern:

  err instanceof AxiosError
    ? err.message
    : 'body' in err && typeof err.body === 'object' && err.body
      ? String(err.body.detail) || ...
      : ...

• The handleError utility in utils.ts is not reused in useAuth, leading to duplicated error handling logic.
• Import paths for shared components (e.g., PasswordInput) in login.tsx and signup.tsx use relative imports instead of the @ alias (e.g., import PasswordInput from '@/components/commonUI/PasswordInput').
• The useAuthContext.tsx file is located in the hooks folder, but it represents a context provider and hook, which would be more appropriately placed in a context directory.

Expected Behavior

• Refactor error handling in useAuth to use a shared utility (e.g., refactor and reuse handleError from utils.ts), ensuring consistent and clear error messages for authentication flows.
• Update all relevant imports in login.tsx and signup.tsx to use the @ alias for shared components, following the project's import conventions.
• Move useAuthContext.tsx from the hooks folder to a new or existing context folder, and update all imports accordingly.
• Consolidate the utils folder and utils.ts file into a single, well-organized location to avoid confusion and duplication. All utility functions should be imported from this unified module.
• Ensure that error messages are user-friendly, translated, and displayed via toast notifications or inline feedback as appropriate.

References

• useAuth.ts in FastAPI Full Stack Template
• utils.ts in FastAPI Full Stack Template