Add portable project transfer API

src/domain/ports/project-transfer.store.ts

@@ -0,0 +1,15 @@
+import type { ProjectStateRestoreCommand } from "../models/project-state-restore-command.model.js";
+import type { ProjectTransferEnvelope } from "../models/project-transfer.model.js";
+
+export interface PreparedProjectTransferReplace {
+  command: ProjectStateRestoreCommand;
+}
+
+export interface ProjectTransferStore {
+  exportProject(projectId: string): ProjectTransferEnvelope | null;
+  prepareReplace(
+    projectId: string,
+    transfer: unknown
+  ): PreparedProjectTransferReplace | null;
+  importDuplicate(transfer: unknown): { projectId: string; name: string };
+}