Cross-Platform Python DLP Packaging (exe, DMG) & Testing fir functionality

I have a Python DLP agent that already runs from the command line. Now I need polished, ready-to-ship install packages for all three major desktop platforms: a signed .exe for Windows, a signed .dmg for macOS, and a Linux build (AppImage, deb, or another widely supported format—whichever you judge most reliable). The packaged application must launch as a background service on boot, continue to expose its command-line controls, and include a small GUI front end so end users can toggle settings without touching the terminal.

Core features that must work out of the box on every platform:
• File monitoring of user-selected folders
• On-the-fly data encryption
• Keyword detection against a configurable list

I’ll need reproducible build scripts (PyInstaller, cx_Freeze, Briefcase, or your preferred toolchain), code-signing instructions, and concise setup documentation so future versions can be cut in a single command. Once you feel the builds are stable, a quick screen-share walkthrough and a short test matrix showing the three key features operating on Windows, macOS, and at least one mainstream Linux distro will serve as final acceptance.