fix: skip cache cleanup during development (#98)

## Summary
- Skip `cleanupCache` when `api.context.action === 'dev'` to retain
cache during dev server runs.

Author: colinaaa

src/index.ts

@@ -199,6 +199,10 @@ ${code}`;
     });
 
     api.onAfterBuild(() => {
+      if (api.context.action === 'dev') {
+        return;
+      }
+
       cleanupCache({
         config: finalConfigPath,
         theme,