Complete modernization of patch 3750 with PatchCards, ContentSidemenu, and footer

- Converted all 45 units to modern PatchCard format (Land: 5, Air: 10, Navy: 8, Structures: 22)
- Converted Structures section: Hives, Kennels, T2 PDs, T2/T3 Artillery, Nukes
- Split units by faction and tier where appropriate
- Introduced neutral badge for universal items (Nuclear Warhead, Nuke Silo)
- Updated sidebar to modern ContentSidemenu with collapsible sections
- Added SidemenuFooter with patch statistics
- Updated site footer with correct patch 3750 information
- Fixed HTML structure with proper closing tags

Author: MrRowey