Add comprehensive installation guide for ThinkPad laptops in INSTALL-laptop.md, covering:
- Prerequisites and preparation steps
- Detailed disk partitioning and formatting instructions
- NixOS installation and configuration process
- ThinkPad-specific optimizations (trackpad, keyboard backlight, power management)
- Troubleshooting section for common issues
- Maintenance and update procedures
Includes ThinkPad T480/X1 Carbon specific configurations and hardware-specific optimizations.
KptltD00M