linux-dev/workstation-v0: install Albert (Fedora) and require it on GNOME

[mdheller]

STACKED on PR #29 (base: feat/linux-dev-workstation-v0-albert-autostart).

Adds an Albert installation lane for GNOME deployments and makes Albert a hard requirement when GNOME is detected.

Changes:

• profiles/linux-dev/workstation-v0/gnome/albert-install.sh installs albert via dnf/rpm-ostree on Fedora (best-effort).
• Installer calls the install script before wiring hotkey/autostart.
• Doctor requires albert when GNOME is detected (fails otherwise).

Notes:

• If Fedora repos do not provide albert, the installer will warn; the doctor will fail until Albert is installed by another method.
• Follow-up can add COPR/RPMFusion discovery or a source build lane if needed.

[mdheller]

Update: added a pragmatic fallback lane for installing Albert when it is not present in native Fedora repos.

• gnome/albert-install.sh now:
  1. tries native repos (dnf / rpm-ostree) first,
  2. if still missing, adds the OBS repo for home:manuelschneid3r and retries.

This is an explicit trust expansion (third-party RPM repo). The script keeps it transparent and best-effort, and still warns if Albert cannot be found.

Next: if we want to avoid third-party RPM repos by default, we can gate this fallback behind an env var (e.g. SOURCEOS_ALLOW_THIRDPARTY_REPOS=1) and make the default path “print instructions” only.

[mdheller]

Update: OBS fallback is now gated.

gnome/albert-install.sh will only add the third-party OBS repo if:

SOURCEOS_ALLOW_THIRDPARTY_REPOS=1

Otherwise it prints explicit instructions (including the exact .repo URL) and exits nonzero so doctor continues to signal the workstation is incomplete.

This preserves the security posture: third-party repo enablement is an explicit, auditable choice.