README: document new checkpoints

README.md

@@ -20,7 +20,13 @@ This model repo contains only the checkpoints needed to reproduce the paper's ev
 
 - four ViT case-study checkpoints total, including the final mixed champion,
   Stage-2c and PO comparison checkpoints, and the legacy replay-era baseline
-- one 1D residual CNN control checkpoint
+- one 1D residual CNN control checkpoint (submitted epoch-6), plus the
+  validation-selected epoch-46 checkpoint used for the paper's convergence test
+- the six XRDBench architecture checkpoints (CNN10, CNN11, PatchTST, BiLSTM,
+  BiGRU, Transformer) trained under the unchanged public SimXRD `train_1`
+  contract and rescored in extinction-group space in the paper; sha256 digests
+  are recorded in `metadata/checkpoint_sha256_manifest.csv` and match the
+  digests embedded in the released evaluation artifacts
 
 It does **not** contain: