Add portable project transfer API

src/shared/validation/project-transfer.schemas.ts

@@ -0,0 +1,18 @@
+import { z } from "zod";
+import { expectedProjectRevisionSchema } from "./project-command.schemas.js";
+
+export const importProjectTransferSchema = z.discriminatedUnion("mode", [
+  z
+    .object({
+      mode: z.literal("replace"),
+      expectedRevision: expectedProjectRevisionSchema,
+      transfer: z.unknown(),
+    })
+    .strict(),
+  z
+    .object({
+      mode: z.literal("duplicate"),
+      transfer: z.unknown(),
+    })
+    .strict(),
+]);