Wraps the release binary in a minimal `OpenPencil.app`
(Info.plist + icon) so a dev run gets the proper Dock name +
icon — an unbundled binary shows the raw executable name and a
generic icon, and the runtime objc2 fallback in `macos_app.rs`
can't fully override that. Run the binary from inside the bundle
(`OpenPencil.app/Contents/MacOS/openpencil-desktop`) and macOS
picks up the bundle identity.
