Split out worker related things to a separate service definition.

Sources/StableDiffusionNode/HostModelService.swift

@@ -0,0 +1,18 @@
+import Foundation
+import GRPC
+import StableDiffusionCore
+import StableDiffusionProtos
+
+class HostModelServiceProvider: SdHostModelServiceAsyncProvider {
+    private let modelManager: ModelManager
+
+    init(modelManager: ModelManager) {
+        self.modelManager = modelManager
+    }
+
+    func loadModel(request: SdLoadModelRequest, context _: GRPCAsyncServerCallContext) async throws -> SdLoadModelResponse {
+        let state = try await modelManager.createModelState(name: request.modelName)
+        try await state.load(request: request)
+        return SdLoadModelResponse()
+    }
+}