Move quixos protocol to repository root

src/descriptor-check.ts

@@ -0,0 +1,31 @@
+#!/usr/bin/env node
+import fs from "node:fs";
+import {
+  packageDescriptorToJson,
+  parsePackageDescriptorTextproto,
+  validatePackageDescriptor,
+} from "./descriptor.js";
+
+const usage = (): never => {
+  console.error("Usage: quixos-descriptor-check <descriptor.txtpb>");
+  process.exit(1);
+};
+
+const path = process.argv[2] ?? usage();
+
+try {
+  const descriptor = parsePackageDescriptorTextproto(
+    fs.readFileSync(path, "utf8"),
+  );
+  const errors = validatePackageDescriptor(descriptor);
+  if (errors.length > 0) {
+    for (const error of errors) {
+      console.error(error);
+    }
+    process.exit(1);
+  }
+  process.stdout.write(`${packageDescriptorToJson(descriptor)}\n`);
+} catch (error) {
+  console.error(error instanceof Error ? error.message : String(error));
+  process.exit(1);
+}