fix: Handle existing username error on Google callback

[weebao]

The google callback page would load indefinitely when a user tried to save a profile with a username that already existed. This was because the frontend was not handling the error response from the backend.

This commit fixes the issue by updating the onResult and adding an onError callback to the superForm instance on the google callback page. The onResult callback now handles the failure case and displays an error message on the username field. The isSubmitting state is also reset correctly, preventing the form from hanging.

Also, updated the changelog.

[Copilot]

Pull Request Overview

This PR fixes a bug where the Google OAuth callback page would hang indefinitely when a user attempted to create a profile with an existing username. The fix ensures proper error handling and UI state management by adding error callbacks and resetting the submission state.

• Added proper error handling for username conflicts in the Google callback form
• Added onError callback to reset form submission state
• Updated the changelog to document the bug fix

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/routes/(auth)/login/google/callback/+page.svelte	Added error handling logic to prevent infinite loading and display username errors
docs/changes.md	Updated changelog with the bug fix entry

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[weebao]

It doesn't work