Related to #630
Proxmox 8.3+ changed the VM status API to return the `agent` field as an
object ({"enabled":1,"available":1}) instead of an integer (0 or 1). This
caused Pulse to incorrectly treat VMs as having no guest agent, resulting
in missing disk usage data (disk:-1) even when the guest agent was running
and functional.
The issue manifested as:
- VMs showing "Guest details unavailable" or missing disk data
- Pulse logs showing no "Guest agent enabled, querying filesystem info" messages
- `pvesh get /nodes/<node>/qemu/<vmid>/agent/get-fsinfo` working correctly
from the command line, confirming the agent was functional
Root cause:
The VMStatus struct defined `Agent` as an int field. When Proxmox 8.3+ sent
the new object format, JSON unmarshaling silently left the field at zero,
causing Pulse to skip all guest agent queries.
Changes:
- Created VMAgentField type with custom UnmarshalJSON to handle both formats:
* Legacy (Proxmox <8.3): integer (0 or 1)
* Modern (Proxmox 8.3+): object {"enabled":N,"available":N}
- Updated VMStatus.Agent from `int` to `VMAgentField`
- Updated all references to `detailedStatus.Agent` to use `.Agent.Value`
- The unmarshaler prioritizes the "available" field over "enabled" to ensure
we only query when the agent is actually responding
This fix maintains backward compatibility with older Proxmox versions while
supporting the new format introduced in Proxmox 8.3+.