On macOS (and some Glances configurations) the /api/4/all endpoint
omits the quicklook key, causing a Zod invalid_type error and crashing
the system health widget. Mark quicklook as .optional() in allSchema
and add a null-safe fallback (`?? "Unknown"`) for cpuModelName.
Fixes#5728
Co-authored-by: Matt Van Horn <455140+mvanhorn@users.noreply.github.com>