feat(vm-provision): declare the guest agent per guest OS, Linux only

Follows napalm-device-types 3.0, which replaces GUEST_AGENT_PACKAGES /
GUEST_AGENT_RUNCMD with GUEST_AGENTS = {guest_os: (packages, runcmd)}.
VMware lists Linux with open-vm-tools, as before, and refuses any other
guest_os before anything is created: BSD guests on VMware are optional
for now (NetOrk/netork#801).

The NoCloud network-config moved to napalm-device-types
(`provisioning.network_config`), which Proxmox now uses as well; the seed
module's copy is gone, and the tests check that the generic one is used.

CHANGELOG.md

@@ -15,6 +15,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `reboot_host` on ESXi, refused outside maintenance mode.
 - Declares `open-vm-tools` as the guest agent for provisioned VMs.
 
+### Changed
+- The guest agent is declared per guest OS (`GUEST_AGENTS`, napalm-device-types
+  3.0); VMware provisions Linux guests only and refuses any other `guest_os`.
+- The NoCloud network-config comes from napalm-device-types
+  (`provisioning.network_config`), which Proxmox uses as well.
+
 ## [0.1.0] - 2026-09-24
 
 ### Added