fix(release): publish packaged desktop bundles

[rjckkkkk]

Problem

package-release.sh includes the two Linux desktop archives in checksums.txt, but publish-release-assets.sh previously uploaded only the four standalone binaries and the checksum file.

The public v0.5.0 Release was repaired immediately by uploading both archives and regenerating the checksum manifest from the published assets.

Fix

• upload either desktop archive whenever packaging produced it
• retain the archives as optional for environments without desktop icon assets
• add a regression contract for both filenames and the upload array

Validation

• bash -n scripts/publish-release-assets.sh
• go test ./internal/ci
• downloaded all seven public v0.5.0 assets and passed every entry in checksums.txt