Let less-technical writers open OpenWriter as a native macOS app

## Contribution available A working local macOS launcher prototype is ready. This issue is to confirm the desired packaging and support direction before I turn it into a focused contribution. ## Problem OpenWriter is a local writing tool, but today a person may need to start or manage a local service from Terminal before they can use it. For writers who do not use developer tools, that makes an otherwise approachable writing experience effectively inaccessible. ## Intended experience A writer should be able to open OpenWriter from Finder or the Dock, just as they would any other Mac app. The app should reconnect to an already-running local service or start it when needed, show a useful loading or recovery state while it becomes ready, and open the workspace in a standard Mac window with normal menus, shortcuts, window controls, and clipboard behavior. The writer should not need to learn about ports, processes, Node, or terminal commands. ## Contribution scope This is a local desktop wrapper, not a hosted service or a replacement for the browser workflow. A production-ready contribution needs a repeatable install and update path that works on a supported Mac without relying on a developer's personal runtime configuration. ## Done when A less-technical writer can install, open, and use OpenWriter as a normal macOS application, while people who prefer the existing browser workflow can continue using it unchanged.