459: fix Docker Desktop compat and remote wg0 reuse

[evgheni7]

Fixes #459.

• k3s-docker: publish 6443 on a dynamic host port, add 127.0.0.1/localhost TLS SANs, rewrite kubeconfig to https://127.0.0.1:<hostPort> so the cluster is reachable from the host on Docker Desktop and native Docker.
• k3s image bumped to v1.32.13-k3s1 to avoid the klog nil pointer panic in v1.32.2.
• remote node: re-address wg0 on the remote when the env subnet changes, fixing Nexthop has invalid gateway after recreating an environment.
• remote cleanup: remove the local peer from remote wg0 so the interface tears down cleanly.