feat: backend gate fallback + metric_diff docs + submit_sft fix

- Auto-inject human-review gate when agent asks question but forgets gate entry
- Add complex_dev/complex_base field docs to program.md metric_diff table
- Fix submit_sft.sh minor issues
- jupyter_runtime improvements

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

skills/model-iteration/scripts/submit_sft.sh

@@ -19,7 +19,9 @@ SFT_RUNDIC=${1:?usage: $0 <SFT_RUNDIC> [PREV_RUNDIC]}
 PREV_RUNDIC=${2:-$((SFT_RUNDIC-1))}
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
-ROOT=${AUTORESEARCH_ROOT:-/mnt/wangsenhao/autoresearch-zk}
+# chat-isolated 时代 AUTORESEARCH_ROOT == AUTORESEARCH_CHAT_ROOT；优先用 chat
+# root，避免 agent 没 export AUTORESEARCH_ROOT 时回退到全局共享路径（已废弃）。
+ROOT=${AUTORESEARCH_ROOT:-${AUTORESEARCH_CHAT_ROOT:-$(dirname "$SCRIPT_DIR")}}
 TPL=${SFT_TRAIN_JOB_TEMPLATE:-$SCRIPT_DIR/sft_train_job.yaml.tpl}
 YAML=/tmp/sft_train_job_r${SFT_RUNDIC}.yaml