chooseStatus() had a special case for SourceAvailability that always
returned 'incoming', overriding SourceAgent (priority 3) and Proxmox
(priority 2). When an availability probe reported offline, it overwrote
the Proxmox API's online status on every poll cycle, causing node-level
CPU/Mem/Disk to show — because isOnline() gated metric rendering.
Also fix markStaleLocked() to recompute status from remaining fresh
sources via aggregateStatus() instead of blindly downgrading online to
warning. This ensures correct status when high-priority sources go stale
but lower-priority sources are still fresh.
rcourtman
85f389c1a4