Clarify HOTP/TOTP documentation to address USB Security dongle compatibility confusion

- [x] Enhanced Prerequisites page with technical clarifications - [x] Improved FAQ section with HOTP/TOTP explanations - [x] Clarified Keys page with TPMTOTP details - [x] Updated terminology to use "HOTP verification" - [x] Fixed broken links and improved references - [x] **Simplified all explanations to address layman user confusion** - [x] Clarified that Heads generates TOTP codes (not dongles) - [x] Clarified that Heads generates HOTP codes for verification - [x] Removed confusing technical jargon - [x] Focused on practical user needs rather than implementation details - [x] Made USB Security dongle role clearer - [x] Used simple language: "Heads generates" instead of technical protocol details - [x] Emphasized practical outcomes: "codes match = firmware is safe" - [x] **Addressed comprehensive review feedback** - [x] Clarified OpenPGP requirement for ALL dongles - [x] Simplified HOTP vs non-HOTP board variant explanation - [x] Fixed table format consistency (consistent emoji usage) - [x] Distinguished "OpenPGP only" vs "Full support" compatibility levels - [x] Removed confusing technical protocol explanations - [x] Referenced authoritative Nitrokey documentation - [x] Made board availability clearer for different configurations - [x] **Fixed all broken permalinks** - [x] Updated FAQ link to use correct Jekyll permalink `/Prerequisites` instead of file path - [x] Fixed anchor to use `#usb-security-dongles-aka-security-token-aka-smartcard` (main USB dongles section) - [x] Verified all Prerequisites links throughout repository use correct Jekyll permalinks - [x] All links now work properly in local testing environment <!-- START COPILOT CODING AGENT TIPS --> --- ✨ Let Copilot coding agent [set things up for you](https://github.com/linuxboot/heads-wiki/issues/new?title=✨+Set+up+Copilot+instructions&body=Configure%20instructions%20for%20this%20repository%20as%20documented%20in%20%5BBest%20practices%20for%20Copilot%20coding%20agent%20in%20your%20repository%5D%28https://gh.io/copilot-coding-agent-tips%29%2E%0A%0A%3COnboard%20this%20repo%3E&assignees=copilot) — coding agent works faster and does higher quality work when set up for your repo.