Replaces the combined locale dropdown with two independent selectors:
- Language dropdown: flag + 2-letter code (e.g., '🇺🇸 EN')
- Currency dropdown: symbol + 3-letter code (e.g., '$ USD')
Changes:
- test-index.html: Split combined dropdown into nav-dropdown--language and nav-dropdown--currency
- clavitor.css: Add styles for split selectors with 8px gap, mobile stacking
- JavaScript: Independent state management for each selector
Design requirements met:
- Both dropdowns fit within nav bar without wrapping
- Mobile: stack vertically in hamburger menu
- 8px gap between selectors using existing spacing
fixes#10
Author: Emma <emma-20250409-001>