Chore: Untrack all files within the `.vscode/` directory except `extensions.json`

[nick-y-ito]

Overview

This pull request excludes all files within the .vscode directory except extensions.json to prevent personal IDE settings from being included in the git history.

Note

Assignee Checklist:

• [x] The naming convention of the PR title is correct (See the comment at the top of this template)
• [x] The base branch is correct (See: Types of Branches)
• [x] The branch name follows the Branch Naming Conventions
• [x] The correct assignees and reviewers have been designated for this PR
• [x] The coding style follows the Coding Style Guide
• [x] All the related issues are associated with this PR
• [x] All criteria in the associated issues are met (please tick the checkboxes)
• [x] My changes do not generate new warnings or errors (especially in the console)

Reviewer Checklist:

• [x] Double-check the "Assignee Checklist"
• [x] The code follows the generic best practices and our Coding Style Guide
• [x] The code is well-commented and easy to understand
• [x] The UI changes accurately reflect the provided design