chore: メールアドレスでログインできるようにした

[laminne]

close #381

概要

• メールアドレスでログインできるようにしました．
• バックエンド側が完成したらdraftを解除します．

[Copilot]

Pull Request Overview

This PR enables login functionality using email addresses instead of account names, updating both the frontend form and API integration to support email-based authentication.

• Changed login form input from account name to email address with appropriate validation
• Updated API function to accept email parameter instead of name parameter
• Modified form labels and placeholders to reflect email-based login

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
app/routes/login.tsx	Updated login form to use email input field and modified action handler to process email instead of name
app/lib/api/login.ts	Changed LoginArgs interface and login function to use email parameter instead of name

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[Copilot]

Pull Request Overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

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