[w3irdrobot]

Summary

References #1374.

The reported bundle launches from a terminal, but GNOME does not reliably execute its shell-script AppRun on double-click, and File Roller cannot launch files inside the archive. This change makes the existing supported installation and application-menu launch path discoverable; it does not make AppRun double-clickable.

• Include README.txt in both Dev and Prod Linux bundles with extraction, installation, and GNOME application-menu instructions.
• Point installer completion output to the application menu and quote the terminal fallback command.
• Document the GNOME/File Roller limitation without recommending changes to file associations or script-execution security settings.
• Test shipped instructions and real GLib desktop-entry launching for both profiles after removing the download folder.

Validation

• Component pinned Nix shell: python3 -m unittest discover -s scripts -p 'test_linux*.py' — 43 passed.
• Component pinned Nix shell: python3 -m unittest discover -s scripts -p 'test_release_packaging.py' — 50 passed, 2 skipped.
• Root nix flake check --no-update-lock-file — passed on x86_64-linux.
• git diff --check — passed.

Ubuntu 24.04 / GNOME 46 GUI behavior and a full real release bundle build have not been verified. Full Rust component gates were not run locally; the change is limited to packaging guidance, installer output, and Python tests.

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