docs(operations): LLM usage-attribution research catalog

Deep-research reference for per-consumer tracking of the fleet endpoints:
measured baseline (no identity anywhere; frank-zealot /metrics 501), the
seven identity layers, engine-native/gateway/tracing/network catalogs with
citations, and a phased adoption plan.

serverAppConfigs-docs/Operations/index.md

@@ -23,6 +23,9 @@ Procedures for operating the fleet. The LLM-specific pages live under
   posture, whole-fleet audit, bulk redaction, stash audits
 - [[SSH and Remote Access]] — passwordless bootstrap without sshpass, fish
   login shells, GUI-hang diagnosis over ssh
+- [[LLM Usage Attribution]] — who-is-using-the-fleet-LLMs research catalog:
+  engine-native identity, gateways, tracing, network/host attribution, and
+  the phased plan
 
 ## Related
 - [Observability Provisioning](../Infrastructure/Observability%20Provisioning.md)