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

scripts/archive/test-trpc-client.ts

@@ -42,7 +42,7 @@ async function main() {
     return;
   }
 
-  const result = await caller.experiments.get({ id: exp.id });
+  const result = await caller.experiments!.get({ id: exp.id });
 
   console.log(`✅ Fetched experiment: ${result.name} (${result.id})`);