Predome public-data reproduction

Run: python3 build-case-evidence.py --data-dir .
Python 3 standard library only. No model key is required.
The default run is offline; --refresh-pubchem explicitly requests the official reference again.
Run timestamps and elapsed time change; source bytes and result_sha256 should remain the same.
These are 2017 public processed RNA-seq counts from the original investigators, not a Predome wet-lab experiment.
The displayed ten-gene selection is not a genome-wide screen; no significance, causality or efficacy is established.
