README update

Author: namedgraph

CLAUDE.md

@@ -80,9 +80,18 @@ find ./document-hierarchy/ -name '*.sh' -exec bash {} \;
 - `ServiceContext` decouples HTTP infrastructure from `Service`, holding dataspace and service metadata separately
 - Dataspace metadata and service metadata are split in configuration; types for `lapp:endUserApplication`/`lapp:adminApplication` are inferred on the fly from `system.trig`
 
+### Dataspaces
+Since v5.1.0, a single LDH instance supports multiple **dataspaces**, each identified by a distinct subdomain (origin). Each dataspace is a pair of applications: an end-user app (`<subdomain>`) and an admin app (`admin.<subdomain>`), routed by nginx via wildcard subdomain matching.
+
+Configuration is split across two files:
+- `config/dataspaces.trig` — public metadata: origins (`lapp:origin`), ontologies (`ldt:ontology`), stylesheets (`ac:stylesheet`)
+- `config/system.trig` — internal wiring: maps apps to SPARQL services (`ldt:service`) and assigns types (`lapp:AdminApplication`/`lapp:EndUserApplication`)
+
+Multiple dataspaces can share the same backend SPARQL service.
+
 ### Service Architecture
 The application runs as a multi-container setup:
-- **nginx**: Reverse proxy and SSL termination
+- **nginx**: Reverse proxy and SSL termination (wildcard subdomain routing for dataspaces)
 - **linkeddatahub**: Main Java application (Tomcat)
 - **fuseki-admin/fuseki-end-user**: Separate SPARQL stores
 - **varnish-frontend/varnish-admin/varnish-end-user**: Caching layers

README.md

@@ -153,7 +153,13 @@ The following tools are required for CLI scripts in the `bin/` directory:
 
   ### Dataspaces
 
-  Dataspaces are configured in [`config/system.trig`](https://github.com/AtomGraph/LinkedDataHub/blob/master/config/system.trig). Relative URIs will be resolved against the base URI configured in the `.env` file.
+  Since version 5.1.0, a single LinkedDataHub instance supports multiple **dataspaces**, each identified by a distinct subdomain (origin). Each dataspace consists of a pair of applications: an end-user app (e.g. `https://northwind-traders.demo.localhost:4443`) and an admin app on the `admin.` subdomain (e.g. `https://admin.northwind-traders.demo.localhost:4443`).
+
+  Dataspace configuration is split across two files:
+  - [`config/dataspaces.trig`](https://github.com/AtomGraph/LinkedDataHub/blob/master/config/dataspaces.trig) — public metadata: origins (`lapp:origin`), ontologies, stylesheets
+  - [`config/system.trig`](https://github.com/AtomGraph/LinkedDataHub/blob/master/config/system.trig) — internal wiring: SPARQL service bindings and application types (`lapp:AdminApplication`/`lapp:EndUserApplication`)
+
+  To add a new dataspace, add corresponding entries to both files. Relative URIs will be resolved against the base URI configured in the `.env` file.
 
 _:warning: Do not use blank nodes to identify applications or services. We recommend using the `urn:` URI scheme, since LinkedDataHub application resources are not accessible under their own dataspace._