Add OpenAPI schema generation and validation for API routes

src/openapi/serialize.ts

@@ -0,0 +1,19 @@
+function sortJson(value: unknown): unknown {
+  if (Array.isArray(value)) {
+    return value.map(sortJson);
+  }
+
+  if (value && typeof value === 'object') {
+    return Object.fromEntries(
+      Object.entries(value)
+        .sort(([left], [right]) => left.localeCompare(right))
+        .map(([key, child]) => [key, sortJson(child)]),
+    );
+  }
+
+  return value;
+}
+
+export function serializeOpenApiDocument(document: unknown) {
+  return `${JSON.stringify(sortJson(document), null, 2)}\n`;
+}