fix: remove unused zod-to-json-schema dependency and update JSON schema conversion to use Zod v4's built-in method

Author: hotlong

packages/spec/package.json

@@ -112,8 +112,7 @@
     "@vitest/coverage-v8": "^4.0.18",
     "tsx": "^4.21.0",
     "typescript": "^5.3.0",
-    "vitest": "^4.0.18",
-    "zod-to-json-schema": "^3.25.1"
+    "vitest": "^4.0.18"
   },
   "dependencies": {
     "zod": "^4.3.6"

packages/spec/scripts/build-schemas.ts

@@ -3,7 +3,6 @@
 import fs from 'fs';
 import path from 'path';
 import { z } from 'zod';
-import { zodToJsonSchema } from 'zod-to-json-schema';
 import * as Protocol from '../src/index';
 
 const OUT_DIR = path.resolve(__dirname, '../json-schema');
@@ -118,10 +117,9 @@ for (const [namespaceName, namespaceExports] of Object.entries(Protocol)) {
         const schemaName = key.endsWith('Schema') ? key.replace('Schema', '') : key;
 
         try {
-          // Convert to JSON Schema
-          const jsonSchema = zodToJsonSchema(value, {
-            name: schemaName,
-            $refStrategy: "none" // We want self-contained schemas for now
+          // Convert to JSON Schema using Zod v4's built-in toJSONSchema()
+          const jsonSchema = z.toJSONSchema(value, {
+            target: 'draft-2020-12',
           });
 
           const fileName = `${schemaName}.json`;