Use hardcoded agent instead of generating from package.json

src/export-node.js

@@ -1,7 +1,8 @@
 import environment from './environment.js';
-import {name, version} from '../package.json';
 
 environment.canAccessScratchAPI = true;
-environment.headers['user-agent'] = `SBDL/${version} (+https://www.npmjs.com/package/${name})`;
+
+// The version here should be incremented if our traffic pattern ever changes significantly
+environment.headers['user-agent'] = 'SBDL/1.0 (+https://www.npmjs.com/package/@turbowarp/sbdl)';
 
 export * from './downloader.js';