Cross-architecture temporal validation: 3 archs x 3 seeds x 2 methods

ResMLP (4-block d=256, with out_ln, CIFAR-10):
  s42:  DFA (a) ep 8,  (b) ep 4,  acc 0.308
  s123: DFA (a) ep 11, (b) ep 4,  acc 0.320
  s456: DFA (a) ep 8,  (b) ep 3,  acc 0.300

ViT-Mini (4-block d=128, cls token + terminal LN, CIFAR-10):
  s42:  DFA (a) ep 1,  (b) ep 3,  acc 0.256
  s123: DFA (a) ep 1,  (b) ep 2,  acc 0.202
  s456: DFA (a) ep 1,  (b) ep 3,  acc 0.253

StudentNet (4-block d=128, NO terminal LN, synthetic alpha=1.0):
  s42:  DFA (a) ep 18, (b) NEVER, acc 0.332
  s123: DFA (a) ep 14, (b) NEVER, acc 0.314
  s456: DFA (a) ep 25, (b) NEVER, acc 0.336

BP: never fires on any seed x any architecture (9/9 sanity passes).

Key cross-architecture finding: diagnostic (b) is specifically the LN-
driven failure mode. Without out_ln, the BP grad never crosses the 1e-7
floor, even though (a) still fires (the residual stream still grows, just
without the LN-cancellation pathology that drives the BP grad to the
floor). This is the causal architectural control: (b) specifically tests
'is terminal-LN gradient cancellation active?' and (a) tests 'is the
residual stream growing without bound?'. They are linked but separable.

This is the §3 cross-architecture validation evidence.

1 files changed, 8 insertions, 2 deletions

diff --git a/protocol/examples/temporal_diagnostic_evolution.py b/protocol/examples/temporal_diagnostic_evolution.py
index 35cf720..af0da84 100644
--- a/protocol/examples/temporal_diagnostic_evolution.py
+++ b/protocol/examples/temporal_diagnostic_evolution.py
@@ -64,7 +64,7 @@ def main():
     import argparse
     p = argparse.ArgumentParser()
     p.add_argument("--seed", type=int, default=42)
-    p.add_argument("--arch", type=str, default="resmlp", choices=["resmlp", "vit"])
+    p.add_argument("--arch", type=str, default="resmlp", choices=["resmlp", "vit", "no_outln"])
     args = p.parse_args()
     if args.arch == "resmlp":
         snapshot_path = os.path.join(
@@ -72,12 +72,18 @@ def main():
         )
         h_key = "hidden_norms"
         g_key = "bp_grad_norms_per_sample_med"
-    else:
+    elif args.arch == "vit":
         snapshot_path = os.path.join(
             REPO_ROOT, f"results/snapshot_vit_v1/snapshot_vit_s{args.seed}.json"
         )
         h_key = "hidden_norms_cls"
         g_key = "bp_grad_per_sample_l2_med"
+    else:  # no_outln (synthetic studentnet without terminal LN)
+        snapshot_path = os.path.join(
+            REPO_ROOT, f"results/snapshot_no_outln_v1/snapshot_noLN_s{args.seed}.json"
+        )
+        h_key = "hidden_norms"
+        g_key = "bp_grad_per_sample_l2_med"
     if not os.path.exists(snapshot_path):
         print(f"snapshot not found: {snapshot_path}")
         return