Add node location access RPCs and operator visibility

README.md

@@ -858,11 +858,16 @@ server:
     allowed_roles: [companion]
     feature_gates:
       ui.canvas: true
+    location:
+      enabled: true
 ```
 
 Methods:
 - `node.register` registers role + declared capabilities for the current connection.
 - `node.capabilities.get` returns negotiated protocol version and enabled capabilities.
+- `node.location.set` updates the node's last-known location (when `server.nodes.location.enabled` is true).
+- `node.location.get` returns the node's stored location payload.
+- `system.location` provides an operator view of registered node locations.
 - `system.capabilities` returns gateway protocol and node policy snapshot.
 
 ## Gateway Request Body Limit