docs: migrate all documentation from lenzu/docs/ to wiki Consolidate all documentation into the GitHub Wiki for centralized discoverability: - Move 19 .md + 1 .puml + 3 images into lenzu/ directory - Move prototypes-desktop-issues.md into prototypes/ directory - Create _Sidebar.md with categorized navigation - Create prototypes-reference.md from lenzu-prototypes README - Rewrite internal cross-doc links to wiki-style (strip .md) - Update scores.md image paths to raw GitHub URLs