[arnestrickmann]

Summary

• hide the native macOS Electron title bar while keeping the traffic lights in their standard position
• add an invisible drag surface and title-bar-aware spacing for desktop app shells, responsive sheets, and splash pages
• keep browser layouts unchanged and provide compatibility fallbacks for older hosted web builds and older desktop shells

Verification

• TMPDIR=/private/var/folders/3j/5rmdnjf90hv3vbxryzdfdz240000gn/T bun run test
• bun run typecheck
• bun run lint
• bun run build
• live macOS Electron visual check
• authenticated web QA at desktop and mobile viewport sizes

Documentation

• packages/desktop/README.md: documented the hidden macOS title bar, preserved traffic lights, and renderer-owned drag surface