otbr comes back with its own network instead of joining the Nest's
NEST-PAN-339C, so the Nest Hub can leave the IoT VLAN (S28-46/S28-48).
The bootstrap Job forms it (dataset init new, channel 15, name
Suedstr28-Thread) on a fresh otbr-thread PVC; the Nest dataset
ExternalSecret is dropped and the Flux Kustomization un-suspended.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>