fn install_dir_of(exe: &Path) -> Option<&Path>Expand description
The installation a (canonical) executable belongs to: on macOS the whole
bundle, not just Contents/MacOS. The outermost .app, because srv’s real
file sits in a nested helper app (AgentMux.app/Contents/Helpers/AgentMux Server.app, scripts/package-macos.sh), and protecting only that would
leave the rest of AgentMux.app open to changes.