Improve auth flow

[MonkyMars]

This pull request introduces several improvements and refactors to the authentication flow in both the backend and frontend. The main changes include better error handling with custom error types, consistent logger usage throughout authentication services, improved feedback and redirection for authentication failures, and UI enhancements for loading states. These updates aim to make the authentication process more robust, maintainable, and user-friendly.

Backend Improvements

• Added custom error types to lib/constants.go for more precise error handling in authentication flows, replacing generic error messages with specific ones like ErrUserAlreadyExists, ErrUsernameTaken, and others.
• Refactored AuthService to consistently use a logger instance, replacing direct log calls and ensuring all handler/service instantiations pass the logger for improved observability. [1] [2] [3] [4] [5] [6] [7]
• Updated error handling in auth_service.go to use the new custom error types, improved logging for failures, and standardized error responses in registration and token refresh flows. [1] [2] [3] [4] [5]
• Changed the behavior in authentication middleware to avoid returning internal Redis errors to clients, increasing security and user experience.

Frontend Improvements

• Enhanced protected route handling in use-auth-context.tsx to only redirect users to the login page when they attempt to access protected routes, improving user experience. [1] [2]
• Updated LoginForm and RegisterForm components to accept an isLoading prop and correctly display loading states when authentication requests are pending, preventing duplicate submissions. [1] [2] [3] [4]
• Improved logout behavior to always redirect users to the login page after logging out, ensuring session termination is clear.

These changes collectively increase the reliability, maintainability, and usability of the authentication system.

[Copilot]

Pull Request Overview

This PR improves the authentication flow by implementing better error handling with custom error types, consistent logger usage, and enhanced user experience with improved loading states and navigation logic.

• Added custom error types to replace generic error messages in authentication services
• Refactored AuthService to consistently use logger instances throughout the codebase
• Enhanced frontend authentication flow with better loading state handling and conditional redirects

Reviewed Changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
apps/server/lib/constants.go	Added custom error constants for authentication operations
apps/server/services/auth_service.go	Integrated logger and replaced generic errors with custom error types
apps/server/api/internal/auth.go	Updated service instantiation to include logger parameter
apps/server/api/middleware/auth.go	Added logger to AuthService instantiation and improved error handling
apps/ui/app/routes/login.tsx	Simplified loading logic and passed loading state to form component
apps/ui/app/routes/register.tsx	Simplified loading logic and passed loading state to form component
apps/ui/app/components/auth/login-form.tsx	Added isLoading prop for better loading state management
apps/ui/app/components/auth/register-form.tsx	Added isLoading prop for better loading state management
apps/ui/app/hooks/use-auth-context.tsx	Enhanced protected route detection to prevent unnecessary redirects
apps/ui/app/hooks/use-auth.ts	Added automatic redirect to login page after logout
apps/ui/app/lib/api-client.ts	Improved auth failure handling to avoid triggering on expected 401s
apps/ui/app/root.tsx	Added suppressHydrationWarning attribute

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