Winui Packaging

The workflow is straightforward: build in Release mode, generate a certificate with `winapp cert generate --manifest` to auto-match your publisher, trust it once with admin rights, then `winapp package` handles staging, resource compilation, and signing in one command. The CI/CD section is clean, showing how to avoid re-run failures with `--if-exists skip`. Most useful when you're moving past F5 debugging and need actual installable packages, whether for internal testing, sideloading to users, or submitting to the Microsoft Store. The troubleshooting table covers the usual certificate trust headaches that trip up first-time packagers.