docs: fix Japanese home page links to use absolute paths

[wo-o29]

📝 Key Changes

Fixed Japanese home page (index.md) links to use absolute paths with /ja/ prefix instead of relative paths. This ensures that clicking links on the Japanese home page keeps users in the Japanese documentation instead of redirecting them to the Korean (root) documentation.

Problem

• Links in the Japanese home page were using relative paths (e.g., /overview, /why)
• VitePress interprets these as root locale paths, redirecting users to Korean documentation
• This broke the expected user experience of staying within the same language

Solution

• Updated all links in the Japanese index.md to include /ja/ prefix
• Links now correctly point to Japanese documentation pages:
  • /overview → /ja/overview
  • /why → /ja/why
  • /principles → /ja/principles
  • /eslint/rules → /ja/eslint/rules

🖼️ Before and After Comparison

Before	After

[vercel]

@wo-o29 is attempting to deploy a commit to the Toss Team on Vercel.

A member of the Team first needs to authorize it.