resolveProxmoxHostSlug trusted attributes.host verbatim, so a value polluted
with prose — lxc:teddycloud carried host="hubris (confirmed via pct config…)" —
became a slug that never resolved, leaving its checks 'down' despite a correct
`hosts` edge. Treat an attribute containing whitespace/parens as invalid and
fall back to the canonical hosts edge.
The audit now reports `polluted_attrs` — entities whose routing-critical
attributes carry prose — so this class is visible instead of a silent
resolution failure.