fix(ci): restore GLIBC 2.35 compatibility for deb packages

[vjnrv]

Summary

PR #3602 resolved the rendering-related colrv1_configure_skpaint crash (issues #2548 and #2982) on newer host distributions (like Ubuntu 24.04+ and Fedora 40+) by bumping the Linux AppImage build container to ubuntu:24.04. This ensured that the bundled WebKitGTK in the AppImage matched the FT_ColorStopIterator layout changes introduced in FreeType 2.13+.

However, upgrading the build container to ubuntu:24.04 had the unintended side effect of raising the minimum GLIBC floor of the entire build pipeline to 2.39. As a result, the generated .deb packages (which were compiled inside the same container) now require GLIBC_2.38 or higher, breaking installations on stable distributions such as Ubuntu 22.04 LTS (GLIBC 2.35) and Debian 12 (GLIBC 2.36).

Because .deb packages do not bundle WebKitGTK (they use the system's libwebkit2gtk package), they are completely unaffected by the FreeType struct mismatch. The system-provided WebKitGTK is already compiled against the system-provided FreeType layout. Thus, there is no technical requirement to compile .deb packages on Ubuntu 24.04.

By splitting the Linux build environments, we can restore first-class support for Ubuntu 22.04 LTS and Debian 12 via the .deb package while fully preserving the AppImage fixes for newer hosts.

Solution

• Split Linux Build Pipelines:
  • .github/workflows/linux-canary.yml: Refactored the build job to use a strategy.matrix separating target platforms.
    • AppImage is built in ubuntu:24.04 to maintain FreeType 2.13+ layout compatibility.
    • Debian is built in ubuntu:22.04 to restore the GLIBC 2.35 floor.
    • Updated steps (tauri build, fix-appimage.sh gating, artifact collection, and uploading) to be matrix-aware.
  • .github/workflows/release.yml:
    • Isolated the existing release-linux job to only build appimage on ubuntu:24.04.
    • Added a new release-linux-deb job running on ubuntu:22.04 to compile the deb package only.
    • Updated the assemble-manifest job to wait for both release-linux and release-linux-deb before completing the release draft.

References

• Resolves the compatibility regression introduced in [PR chore(ci): bump Linux AppImage build container to ubuntu:24.04 #3602]

Validation

• The workflows have been validated by running them on a fork:
  • The AppImage matrix job successfully compiled the AppImage package on ubuntu:24.04.
  • The Debian matrix job successfully compiled the .deb package on ubuntu:22.04.
  • The generated .deb package was downloaded and verified to install and launch without GLIBC errors on an Ubuntu 22.04 LTS system (GLIBC 2.35).