evaluate_baseline looks for <output_dir>/norm_stats_fold{N}.json per fold
(matching the convention written by train_baseline_supervised.rs:812).
train_baseline_rl never produced this file — the fxcache has a single
<hex_key>.norm_stats.json written by precompute_features, which RL
training uses implicitly for pre-normalized features but never copies to
the per-fold paths evaluate wants. Result (L40S train-7r9zf):
Error: NormStats not found at /workspace/output/norm_stats_fold0.json
- cannot evaluate without training-set statistics (computing from test
data would introduce lookahead bias). Run training first to generate
this file.
WARN: Evaluation failed, continuing
Evaluate fails gracefully but no report is produced.
Fix: new helper `fxcache::norm_stats_path_for_key(data_dir, override, cache_key)`
returns the canonical <hex_key>.norm_stats.json path that sits next to
the .fxcache file. train_baseline_rl resolves this once after the fxcache
load (falling back to None if the key is zero — i.e., DBN fallback path
with no precomputed stats) and copies it into the output dir as
norm_stats_fold{N}.json for every fold processed.
The RL-side fxcache norm stats are fold-independent (one z-score per
cache key, applied to all walk-forward windows), so the per-fold copies
are intentional duplicates of the same file — this matches evaluate's
per-fold lookup semantics without diverging from supervised convention.
Closes task #32.
f988ca384c