Refs #1515
When an upgraded or restored Pulse server no longer recognises an agent's
API token, the report endpoint returns 401. The agent buffered and retried
that report forever with only a generic warning, and the server kept the
node green at its last known agent version because a Proxmox node stays
online via the PVE API poll even after its agent dies.
- Agent: special-case 401 on /api/agents/agent/report. Drop the report
instead of buffering it and log a throttled, actionable error pointing the
operator at the install command to mint a fresh token.
- Installer: verify_agent_server_registration now tells a rejected token
(401/403) apart from "agent has not reported yet" and prints the recovery
steps at install time instead of a vague soft warning.
- Status layer: resourceFromHost flags a stale agent (its host marked
offline by the staleness evaluator) and carries the agent's own last
report time. Coalescing keeps a node online via the PVE source but the
dead agent stays flagged, so its version is no longer presented as current.
The Machines table renders such versions as "(stale)".
c7dcd90b83