Overhaul return behavior for entity validation

libs/@blockprotocol/type-system/rust/src/schema/entity_type/closed.rs

@@ -35,6 +35,16 @@ pub struct ClosedEntityTypeMetadata {
     pub inverse: InverseEntityTypeMetadata,
 }
 
+impl ClosedEntityTypeMetadata {
+    #[must_use]
+    pub fn is_link(&self) -> bool {
+        self.all_of.iter().any(|entity_type| {
+            entity_type.id.base_url.as_str()
+                == "https://blockprotocol.org/@blockprotocol/types/entity-type/link/"
+        })
+    }
+}
+
 #[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 #[cfg_attr(target_arch = "wasm32", derive(tsify::Tsify))]
 #[serde(rename_all = "camelCase", deny_unknown_fields)]
@@ -160,6 +170,10 @@ impl ClosedMultiEntityType {
         }
     }
 
+    pub fn is_link(&self) -> bool {
+        self.all_of.iter().any(ClosedEntityTypeMetadata::is_link)
+    }
+
     /// Creates a closed entity type from multiple closed entity types.
     ///
     /// This results in a closed entity type which is used for entities with multiple types.

libs/@blockprotocol/type-system/rust/src/schema/entity_type/mod.rs

@@ -1,6 +1,7 @@
 pub use self::{
     closed::{
         ClosedEntityType, ClosedEntityTypeMetadata, ClosedMultiEntityType, EntityTypeResolveData,
+        ResolveClosedEntityTypeError,
     },
     constraints::EntityConstraints,
     reference::EntityTypeReference,
@@ -81,12 +82,6 @@ pub struct EntityTypeDisplayMetadata {
     pub icon: Option<String>,
 }
 
-impl EntityTypeDisplayMetadata {
-    pub const fn is_empty(&self) -> bool {
-        self.label_property.is_none() && self.icon.is_none()
-    }
-}
-
 #[derive(Debug, Clone, Serialize, Deserialize)]
 #[cfg_attr(target_arch = "wasm32", derive(tsify::Tsify))]
 #[serde(rename_all = "camelCase", deny_unknown_fields)]

libs/@blockprotocol/type-system/rust/src/schema/mod.rs

@@ -38,6 +38,7 @@ pub use self::{
         EntityType, EntityTypeReference, EntityTypeResolveData, EntityTypeSchemaMetadata,
         EntityTypeToEntityTypeEdge, EntityTypeToPropertyTypeEdge, EntityTypeValidationError,
         EntityTypeValidator, InverseEntityTypeMetadata, PartialEntityType,
+        ResolveClosedEntityTypeError,
     },
     identifier::{DataTypeUuid, EntityTypeUuid, OntologyTypeUuid, PropertyTypeUuid},
     object::{

libs/@local/graph/api/Cargo.toml

@@ -36,6 +36,7 @@ harpc-types                    = { workspace = true }
 hash-graph-store               = { workspace = true, features = ["utoipa"] }
 hash-graph-temporal-versioning = { workspace = true }
 hash-graph-type-defs           = { workspace = true }
+hash-graph-validation          = { workspace = true }
 hash-status                    = { workspace = true }
 type-system                    = { workspace = true, features = ["utoipa"] }