feat(rpm): add Fedora 44 to build matrix

[linuxnow]

Closes #63.

Summary

One-line change extending arexibo/.github/workflows/rpm.yml's fedora-matrix from ["43"] to ["43", "44"].

Why arexibo first (smallest blast to validate F44 in the shared build-rpm.yml reusable): pure Rust, no Node deps, no Chromium pin. Once this lands green, the same one-line change can roll out to xiboplayer-kiosk, xiboplayer-electron, xiboplayer-chromium, xiboplayer-chrome, xiboplayer-tizen, xiboplayer-webos in follow-up PRs.

Pre-flight checks captured in #63:

• Spec uses Release: 3%{?dist} — .fc44. naming is automatic.
• F44 base packages (rust, cargo, dbus-devel, zeromq-devel, qt6-qtwebengine-devel) all resolvable per the overnight audit (D3).
• Shared build-rpm.yml already declares FEDORA_VERS="43 44" in its R2 upload step — no reusable-workflow change required.
• xiboplayer-release-44-7.fc44.noarch.rpm is already live on R2.

Test plan

• After merge: push a patch tag (e.g. v0.3.3-4) to trigger the workflow.
• Confirm both arexibo-0.3.3-N.fc43.{x86_64,aarch64}.rpm and arexibo-0.3.3-N.fc44.{x86_64,aarch64}.rpm land on R2.
• Confirm update-repos.yml on xiboplayer.github.io regenerates F44 repodata.
• On a Fedora 44 box: sudo dnf install https://dl.xiboplayer.org/rpm/fedora/44/noarch/xiboplayer-release-44-7.fc44.noarch.rpm && sudo dnf install arexibo should succeed.

Risk

Low. Build matrix change only. F44 build failures don't block F43 builds (parallel matrix).

Follow-ups (out of scope)

• Roll out the same matrix bump to the remaining form-factor repos once this PR validates F44 end-to-end.
• D3 flagged a soft caveat on nodejs/nodejs-libs for F44 — kiosk/electron/chromium PRs should pin explicit nodejs22 when they extend.