test(public-api): exercise scoped lifetimes across real HTTP

Construct example calls from fetched structured identity and scope_ref. Add exhaustive public DTO coverage and a transactional external-style provider over TCP to exercise root/self scopes, equal names in distinct scopes, optional and stale refs, deletion/republication, visibility, validator precedence and non-retry of unknown outcomes.

Validation: cargo test -p wip-public-api-example (9 DTO/example tests, 4 real TCP conformance tests); Nix clippy --all-targets -D warnings.

crates/wip-public-api-example/tests/end_to_end.rs

@@ -258,6 +258,40 @@ fn assert_schema_neutral(value: &Value) {
     }
 }
 
+#[test]
+fn scoped_dtos_keep_identity_binding_and_validators_separate() {
+    // Exact literals/destructuring guard the public Rust contract, including
+    // omission of refs rather than requiring a fabricated identity.
+    let reference = wip_protocol::InterfaceReference {
+        scope: "/article-service".into(),
+        name: "catalog::read#raw".into(),
+    };
+    let request = wip_protocol::FetchInterfaceRequest {
+        interface: reference.clone(),
+    };
+    request.validate().unwrap();
+    let wip_protocol::FetchInterfaceResponse {
+        interface,
+        scope_ref,
+        descriptor,
+        validator,
+    } = wip_protocol::FetchInterfaceResponse {
+        interface: reference.clone(),
+        scope_ref: None,
+        descriptor: CatalogDefinition::descriptor(),
+        validator: None,
+    };
+    let target = wip_protocol::InterfaceTarget {
+        reference: interface,
+        scope_ref,
+        validator,
+    };
+    assert_eq!(target.reference, reference);
+    assert!(target.scope_ref.is_none());
+    assert!(target.validator.is_none());
+    assert_eq!(descriptor.format, INTERFACE_FORMAT_V1);
+}
+
 fn root_reference(name: &str) -> wip_protocol::InterfaceReference {
     wip_protocol::InterfaceReference {
         scope: "/".into(),