Brings install.sh to parity with install.ps1's bootstrap surface so the
shared Rust/Tauri bootstrapper (apps/bootstrap-installer) can drive a
macOS/Linux install the same way it drives Windows.
- Accept the PowerShell-style aliases the bootstrapper emits to both
installers: -Commit / -Branch (alongside existing -Manifest / -Stage /
-Json / -NonInteractive).
- Add --include-desktop / -IncludeDesktop. When set, the manifest gains a
'desktop' stage (immediately before 'complete'), and a new install_desktop
runs a root workspace `npm install` + `npm run pack` (electron-builder
--dir, signing auto-discovery disabled) to produce release/mac*/Hermes.app
-- mirroring install.ps1's Install-Desktop / Stage-Desktop.
- The flag is opt-in, exactly like Windows: the signed bootstrap installer
passes it; the Electron app's own first-launch bootstrap and the CLI
one-liner omit it (building the desktop from inside the running app would
clobber it).