fix(vertex): synchronous CustomJob.submit; train UI GCP arch sync

feat: training suite progress, GCS sync, and extended RAG eval

RAG oracle eval: SA-friendly Drive reads, --pull-drive, oracle coverage log

Drive startup provisioning, RAG eval storage on Drive, infer root from unlabelled

RAG oracle eval, RAG-only labeling UI, retrieval and dashboard

Merge value+attribute labels, add header label, RAG eval improvements

Add evaluation, RAG eval, and training comparison scripts