make inbound check optional

configs/control-api.example.yaml

@@ -57,7 +57,12 @@ validators:
   - validator_id: "validator_02"
     os_port_id: "REPLACE_WITH_NEUTRON_PORT_ID_2"
 
-# The three external prober sites, indexed 1-3 (matches ip_queue.siteN_complete).
+# Inbound (prober) checks are OPTIONAL: list here only the external sites
+# you actually run a `prober` on, up to 3 slots (index 1-3, matches
+# ip_queue.siteN_complete — the schema is capped at 3). Leave this list
+# empty to disable inbound checks entirely — the overall result is then
+# based on egress checks alone, and aggregation doesn't wait on any
+# prober. A partial list (e.g. just index 1) only waits on that one site.
 sites:
   - site_id: "site-1"
     index: 1