Add missing

Author: yeikel

contract-typespec/api/package-lock.json

@@ -10,7 +10,8 @@
         "@typespec/rest": "0.73.0",
         "@typespec/sse": "0.73.0",
         "@typespec/streams": "0.73.0",
-        "build": "^0.1.4"
+        "build": "^0.1.4",
+        "typescript": "^5.9.2"
     },
     "scripts": {
         "build": "tsp compile ."