perf(run-swift15-bf16): calib at the vendor big-step shape

MNBT 65536 / seqs 8: MOE-W4.md:244 measures 640 tok/s at a 32k step
vs 930 at 55k — the KLD record's own rate confirmed step size drives
disk-tier prefill. 131k resident tokens fits the 3072 pool (~237k
tokens/rank at fp8). Cuts the 10M-token calibration from ~4.3 h to
~3 h.

scripts/run-swift15-bf16.sh

@@ -63,12 +63,16 @@ case "$MODE" in
     # unparameterisable threshold. Grams are bf16 activations — engine-invariant.
     # Same KV ceiling as kld: the disk-tier weights floor (9.57 GiB) plus
     # ~18 GiB of fixed per-rank claims cap the pool near 3.5 GiB on a 32 GiB
-    # card. 4 slots x 16k fp8 fits; prefill rate is disk-bound, so fewer
-    # resident slots only queues pushes, it does not slow the record.
+    # card — pool minus the 2.17 GiB fixed holds ~237k fp8 tokens a rank, so
+    # the vendor's big-step calibration shape is affordable: MOE-W4.md:244
+    # measures 640 tok/s at a 32k step against 930 at 55k, and the doc's own
+    # run drives MNBT 65536. 8 slots x 16k = 131k resident tokens fits the
+    # pool; the step batches 65k. KLD's observed rate confirmed step size,
+    # not slot count, is the throughput lever.
     IMAGE="stilldeadcode/radiance@$PIN_120"
     mkdir -p "$CALIB_DIR"
     ARGS+=(--port 7770 --vram-kv-mib 3072
-           --max-num-seqs 4 --max-num-batched-tokens 32768
+           --max-num-seqs 8 --max-num-batched-tokens 65536
            --prefix-cache-dir /data/calib-kvcache)
     ;;
   probe)