Close vite dev server before creating new one

Editor assessment

`fix: close vite dev server before creating new one` states the ordering fix and both lifecycle steps plainly; a server or cli scope would have localized it but the terms suffice. Fix fits a lifecycle-order bug. No body explains the failure when a new server started over a live one — port conflicts or leaked handles — the instructive detail, but the subject fully determines the correction. The trailing PR reference is clean. Imperative verb, no trailing period, compact. Minor symptom gap in a clear, correct, publishable message.