Search for the selected text, etc

[gottu91-code]

Tasks

• Complete the following TODO

Todo name: 選択されているテキストを探す
Todo name: 翻訳を登録する
Todo name: 選択されているテキストと翻訳を関連付ける
file: /src/routes/(authed)/learn/+page.svelte
target: add_translation関数のawait show_translation()処理の後

Writing the Issue

• Write each task for this issue using checkboxes
• Write all verbal instructions as tasks
• Add labels and assignees

Before Working on the Issue

• Assign yourself
• Share your screen on Discord
• Write which issue you are starting on Slack
• Git: Fetch the latest main
• Git: Create a branch with the name of the issue

Pre-PR Checks

• Insure that changes include only what is necessary for this PR
• Implement necessary Unit tests
• Implement necessary E2E tests
• Perform functionality checks