Feat: Add language toggle button for existing i18n setup

[p-iknow]

Overview

Add a language toggle button component to switch between English and Korean on the already configured i18n blog.

Current Status

• ✅ Astro i18n configuration completed
• ✅ Route structure (/en/, /ko/) set up
• ✅ Content translation ready

Implementation Tasks

• Create language toggle button component
• Style toggle with Tailwind CSS
• Implement language switching functionality
• Get current language from Astro's i18n context
• Handle language change and navigation
• Add TypeScript types for toggle component

Technical Details

• Use Astro's built-in i18n utilities
• Create reusable toggle component (.astro)
• Handle client-side language switching
• Ensure proper routing between /en/ and /ko/
• Add responsive design with Tailwind

Acceptance Criteria

• Toggle button shows current language (EN/KR)
• Clicking toggles between languages smoothly
• URL updates correctly (/en/page ↔ /ko/page)
• Component is reusable across pages
• Responsive design works on all devices