Add concurrency option

Author: jahooma

evals/buffbench/example.ts

@@ -6,6 +6,7 @@ async function main() {
   const results = await runBuffBench({
     evalDataPath: path.join(__dirname, 'eval-codebuff.json'),
     agents: ['base', 'base2'],
+    commitConcurrency: 10,
     onProgress: (event) => {
       if (event.type === 'agent_error') {
         console.log(`[${event.agent}] ✗ ${event.evalId} error: ${event.error}`)