Critical eval-pipeline bugs found while running the stage-2 model:
1. parse_anomaly_segments only recognized {"segments\:[[s,e]]}; the training
data (data/instruct.py) emits {"anomaly_regions":[{"start","end"}]}.
The model learned the correct format but scored 0 → VUS-PR=0. Now accepts
both schemas + a balanced-brace JSON scanner (the flat regex could not
match nested objects the model emits).
2. qa_judge._extract_json had the same nesting bug — reuse the scanner.
3. Generation truncated at 64-96 tokens (too short for stats JSON) → bumped
to 192 in report + instruct_check.
Report enhancements:
- wire the pure-LLM baseline (series-as-text, no TS modality) so design §5.4
'model vs pure LLM' is actually computed. Heavy predictors built/evaluated
one at a time with GPU cleanup (single 12GB card).
- add QA-judge table across all 6 categories (design §6.5 问答均分).
- add --pure_llm / --max_per_cat flags.
Results (reports/eval-2026-06-30.md): model QA-judge mean 2.45 vs pure_llm
0.88 (2.8x); anomaly localization (VUS-PR) is the weak point — neither
model nor pure_llm localize well; TS-modality ablation change_rate 0.98.