fix: upgrade to Next.js 16.2.1 and resolve bundling issues

- Fixed client bundle contamination by moving child_process-dependent code
- Created standalone /api/robots/command route for SSH robot commands
- Created plugins router to replace robots.plugins for plugin management
- Added getStudyPlugins procedure to studies router
- Fixed trial.studyId references to trial.experiment.studyId
- Updated WizardInterface to use REST API for robot commands

next.config.js

@@ -5,6 +5,9 @@
 import "./src/env.js";
 
 /** @type {import("next").NextConfig} */
-const config = {};
+const nextConfig = {
+  // Mark server-only packages as external to prevent bundling in client
+  serverExternalPackages: ["postgres", "minio", "child_process"],
+};
 
-export default config;
+export default nextConfig;