Add Vue.js integration guide #1336

[Darshan3690]

Description

hi @sumitsaurabh927 and @davidturnbull sir

This PR adds a Vue.js integration guide for Lingo.dev CLI, following the same structure and format as the Laravel integration guide.

What's Included

• Complete Vue.js 3.x project setup with Vue CLI
• Integration with vue-i18n v9 for internationalization
• Language switching component implementation
• Dynamic content examples with interpolation
• Tested workflow from setup to working multilingual app

Testing Completed

• ✅ Created fresh Vue.js project following guide steps
• ✅ Verified all commands execute successfully
• ✅ Tested translation workflow with Lingo.dev CLI
• ✅ Confirmed language switching works across all 5 languages (en, es, fr, de, ja)
• ✅ Verified dynamic content (counter) displays correctly
• ✅ No console errors in browser

Follows Existing Pattern

This guide matches the structure of the Laravel integration guide:

• Same front matter format
• Consistent step-by-step flow
• Similar section organization
• Matching tone and style

Author Credit

If published, please credit:

• GitHub: @Darshan3690