feat(host): resolve published interface references

crates/wip-host/src/lib.rs

@@ -208,6 +208,18 @@ impl InterfaceRegistry {
         })
     }
 
+    /// Resolves a transport-provided opaque reference string in this registry.
+    ///
+    /// The returned value is registry-scoped and suitable for observation or a
+    /// qualified [`CallRequest`]. Unknown or foreign references return `None`;
+    /// constructing arbitrary `InterfaceRef` values is intentionally not part of
+    /// the public API.
+    #[must_use]
+    pub fn resolve(&self, reference: &str) -> Option<InterfaceRef> {
+        let reference = InterfaceRef(reference.to_owned());
+        self.artifacts.contains_key(&reference).then_some(reference)
+    }
+
     /// Observes the descriptor and optional validator for an opaque reference.
     #[must_use]
     pub fn observe(&self, reference: &InterfaceRef) -> Option<InterfaceObservation> {

crates/wip-host/tests/host.rs

@@ -163,6 +163,11 @@ fn registry_exposes_opaque_validated_descriptor_observations() {
     let reader = registry.register(ReaderDefinition, None).unwrap();
 
     assert_ne!(reader.reference().as_str(), "Reader");
+    assert_eq!(
+        registry.resolve(reader.reference().as_str()).as_ref(),
+        Some(reader.reference())
+    );
+    assert!(registry.resolve("wip-interface:unknown:0").is_none());
     let observation = registry.observe(reader.reference()).unwrap();
     assert_eq!(observation.reference, *reader.reference());
     assert_eq!(observation.descriptor.name, reader.reference().as_str());
@@ -174,6 +179,11 @@ fn registry_exposes_opaque_validated_descriptor_observations() {
     let mut other_registry = InterfaceRegistry::new();
     let other_reader = other_registry.register(ReaderDefinition, None).unwrap();
     assert_ne!(reader.reference(), other_reader.reference());
+    assert!(
+        registry
+            .resolve(other_reader.reference().as_str())
+            .is_none()
+    );
 }
 
 #[test]