feat: dropdown nav with submenus + black ops colour theme redesign
- Navigation: 6 top-level items (BASE, TRANSMISSIONS, ARMOURY, INTEL, SAFEHOUSE, COMMS) with dropdown children
- nav.js: renders nested dropdown submenus, mobile tap-to-toggle support
- Theme: tactical green (#00ff41) accent, deep black (#0a0a0a) bg, amber (#c9a227) secondary
- 176 colour replacements across 4 CSS + 3 JS files
- Mobile: responsive dropdowns with slide animation
- Updated navigation.json with full nested structure
jae
139849d632