docs: define financial fabric architecture

README.md

@@ -1,11 +1,20 @@
 # Railiance Fabric
 
-Railiance Fabric defines the repo-owned declaration model for the Railiance
-ecosystem graph.
+Railiance Fabric models the durable infrastructure-responsibility graph of the
+Railiance netkingdom.
 
-It will hold schemas, seed declarations, validation tools, graph queries, and
-State Hub export contracts for services, capabilities, interfaces,
-dependencies, and bindings across Railiance repositories.
+Fabric is bounded by financial and operational accountability: who pays for the
+infrastructure, who is accountable for keeping it alive, and which durable
+interfaces create value across fabric and subfabric boundaries.
+
+It holds schemas, discovery tools, registry services, graph queries, and State
+Hub export contracts for services, machines, repositories, deployables,
+endpoints, ownership, dependencies, and bindings across Railiance deployment
+realities.
+
+See `docs/FabricDiscoveryAndUpdate.md` for the current architecture direction
+for fabric boundaries, king/lord/tenant ownership, discovery, rebuilds, and
+update loops.
 
 ## Validate Declarations