ci: prove Linux upgrade and recovery lifecycle

[turinglambdaai]

Summary

• build two real deb/rpm application versions and retain both artifact sets plus exact hashes and package metadata
• on Debian 13 and Fedora 44, prove initial install, corrupt-upgrade recovery, normal upgrade of metadata and payload, distro-native rollback policy, native-Wayland launch, and complete uninstall
• assert Debian's implicit-downgrade rejection and Fedora's explicit local-RPM rollback followed by a verified re-upgrade to the current payload
• keep AppImage launch as an independent Ubuntu 24.04 gate and update the English/Chinese support contract only behind these executable release gates

Closes #182 after all lifecycle jobs are green.

Local validation

• workflow YAML parsed successfully
• raco test tests/linux-native-installer.rkt tests/documentation.rkt - 186 tests passed
• git diff --check

The real dpkg/DNF transactions are intentionally delegated to the new container jobs; their complete transcripts and installed versions are uploaded even on failure.

[turinglambdaai]

The Fedora failure exposed a real distro-policy difference: Fedora 44 DNF treats an explicitly selected older local RPM as an authorized downgrade, unlike Debian apt's default rejection. Updated the gate and documentation to test the truthful lifecycle: v2 -> explicit v1 rollback with complete payload verification -> v2 re-upgrade recovery -> native Wayland launch. Merged current main and revalidated workflow YAML plus 186 installer/documentation tests.