The panel decides which probes link to which agents (probes dial out): an
auto-link setting plus per-pair manual overrides with a link matrix in the
admin, and the hovered overview card is lifted above its neighbours.
Probes connect to the panel directly and get the agent list as desired state.
CI signs the image digest of agent and probe releases, the panel forwards the
manifest, and a host updater verifies it with a local public key, pulls by
digest and rolls back when the new version is unhealthy.