Add project command API

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

@@ -0,0 +1,17 @@
+import { z } from "zod";
+
+const projectCommandEnvelopeSchema = z.object({
+  schemaVersion: z.number().int().positive(),
+  type: z.string().trim().min(1),
+  payload: z.unknown(),
+});
+
+export const executeProjectCommandSchema = z.object({
+  expectedRevision: z.number().int().nonnegative(),
+  description: z.string().trim().min(1).max(500).optional(),
+  command: projectCommandEnvelopeSchema,
+});
+
+export const executeProjectHistoryCommandSchema = z.object({
+  expectedRevision: z.number().int().nonnegative(),
+});