Fix registration flow to use local authentication

[michaelstingl]

Issue Description

Currently, the registration link in the login page points to an external website (https://toplocs.com/register) instead of using a local registration page within the application. This creates a disjointed user experience and prevents local testing of the registration flow.

Impact on Local Development

This is particularly problematic for local development setups:

• Developers cannot test the complete user onboarding flow locally
• The external link makes it impossible to test registration with the local backend
• New users testing the application locally have no way to create accounts
• Integration testing of the registration process is blocked
• QA engineers cannot verify the full authentication flow in test environments

Expected Behavior

The "SignUp" link on the login page should lead to a local registration page within the application, allowing users to register without leaving the app and connecting to the local backend.

Current Behavior

Clicking the "SignUp" link navigates to https://toplocs.com/register, which is an external site, making local testing impossible.

Proposed Solution

1. Create a new RegisterPage.vue component for handling user registration
2. Add a route for /register in the router configuration
3. Update the "SignUp" link in LoginPage.vue to point to the local route
4. Enhance the user composable with a register function to handle API requests

Technical Details

The registration API endpoint /api/user is already implemented in the backend, but needs to be properly integrated with the frontend. The solution should ensure that:

• Registration requests go to the same backend URL configured in the .env file
• Authorization tokens are properly stored after successful registration
• Error handling is consistent with the login flow

Related PR

A potential solution has been implemented in michaelstingl#1

Benefits

• Improved user experience by keeping users within the application
• Better testability of the registration flow in local development
• Consistent authentication experience across the application
• Simplified onboarding for new developers
• Complete end-to-end testing capability in all environments