Add MCP deployment note to runbook

- MCIAS is not managed by MCP due to circular dependency
- Points operators to existing systemd deployment sections

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

RUNBOOK.md

@@ -461,6 +461,19 @@ See `dist/mcias.conf.docker.example` for the full annotated Docker config.
 
 ---
 
+## MCP Deployment
+
+MCIAS is **not** managed by MCP and does not run on rift. Because MCIAS is the
+authentication root for the entire platform — including MCP itself — running it
+under MCP would create a circular dependency. Instead, MCIAS runs as a systemd
+service on a separate VPS (`svc.metacircular.net`).
+
+All deployment, upgrades, and operational tasks use systemd directly on the VPS.
+See the [Installation](#installation), [Routine Operations](#routine-operations),
+and [Upgrading](#upgrading) sections above for the relevant procedures.
+
+---
+
 ## Troubleshooting
 
 ### Server fails to start: "open database"