CAT-N6: the keeper's health tool nats_keeper_health, which the process keeper's tool check asks

It reads the keeper's status from its own state asked, what the keeper holds,
and how many accepted verdicts wait on its consumer <node>_nats_keeper on
EVENTS from the monitoring endpoint, and answers HealthOf's judgement:
unhealthy, naming why, past the three-minute bound; the entries refused,
waiting and past the raise mark named beside.

Claude-Session: https://claude.ai/code/session_01JG73KJNrH5EgFXMKKYSrig

modules/nats/module.json

@@ -119,7 +119,8 @@
     "nats_create",
     "nats_apply",
     "nats_recreate",
-    "nats_drop"
+    "nats_drop",
+    "nats_keeper_health"
   ],
   "guards": [
     8222