docs: Add Korean translation for Usage with NuxtJS document

[Gaic4o]

Background

This PR adds a Korean translation of the "Usage with NuxtJS" documentation.

Key Changes

• Complete Korean translation of the NuxtJS and FSD integration guide
• Fixed inconsistencies in the original document:
  • Standardized file naming: the original document uses both router.config.ts and router.options.ts inconsistently. This translation consistently uses router.options.ts throughout
  • Added numbered steps (1️⃣, 2️⃣, 3️⃣) in the file-based routing section to improve clarity
  • Added more descriptive section headings in the file-based routing part to better organize the content