Add DMG installer with drag-to-Applications support

Improve installation experience for macOS users by creating a DMG
installer that provides a standard drag-to-Applications installation
interface. This follows macOS app distribution best practices and
makes the initial app setup more intuitive.

- Implemented `just dmg` recipe to generate installer
- Uses standard macOS drag-to-install metaphor
- Simplifies first-time user onboarding

Author: bartTC

CHANGELOG.md

@@ -6,6 +6,7 @@ All notable changes to this project will be documented in this file.
 
 ### Added
 - Privacy Policy document (PRIVACY.md)
+- DMG installer with drag-to-Applications window (`just dmg`)
 
 ### Changed
 - App renamed from "CF Cache Status" to "Cache Status"