perf(telemetry): stop migration hook from endlessly rsyncing large node_modules by guarding with marker file

lib/dev-container.ts

@@ -442,7 +442,7 @@ export async function execInDevContainer(
     if (projectRow?.slug) {
       const slug = projectRow.slug;
       const migrationCmd =
-        `if [ -d "/workspace/${slug}" ] && [ ! -d "/workspace/.git" ]; then ` +
+        `if [ ! -f "/workspace/.vibn-migration-root-fix" ] && [ -d "/workspace/${slug}" ] && [ ! -d "/workspace/.git" ]; then ` +
         `rsync -a "/workspace/${slug}/" "/workspace/" 2>/dev/null; ` +
         `mv "/workspace/${slug}" "/workspace/.legacy-nested-${slug}-$(date +%s)" 2>/dev/null; ` +
         `echo "Migrated nested repo from /workspace/${slug}" > /workspace/.vibn-migration-root-fix; ` +