rugnux_anomalous.py: read ANODE peak labels for any scatterer, not just sulfur

ANODE names its ranked peaks after the SFAC element it was given, so the labels
read S1, S2, ... on a sulfur case but FE1, MN1, ZN1, SE1 as soon as the model
carries a heavier scatterer. The parser matched "S" followed by digits, so on
any such dataset it dropped the ENTIRE peak list and the dataset failed the gate
as "no peaks" - however strong its signal actually was. One heme case reported
no peaks when its true top peak is 13.79 sigma at 3.02x the off-site floor.

The bug is silent and it mis-gates exactly the datasets most likely to widen the
arbiter set, since a heavy scatterer is what makes a weakly diffracting crystal
usable as an arbiter in the first place.

Byte-identical on the standing all-sulfur set, verified by diffing the gate table
before and after.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

rugnux_anomalous.py

@@ -98,6 +98,7 @@ if __name__ == "__main__" and not os.environ.get("RUGNUX_ANO_BOOTSTRAPPED"):
 import argparse
 import json
 import math
+import re
 import shutil
 import statistics
 import datetime
@@ -111,6 +112,12 @@ CCP4_SETUP_DEFAULT = "/opt/xtal/ccp4-9/bin/ccp4.setup-sh"
 # leading-letters rule gets them wrong.
 ANOM = {"S", "CL", "P", "CA", "K", "FE", "ZN", "SE", "BR", "CU", "MN", "NI", "CO", "I"}
 
+# ANODE names its ranked peaks after the SFAC element it was given, so the labels read
+# S1, S2, ... on a sulfur case but FE1, MN1, ZN1, ... as soon as the model carries a
+# heavier scatterer.  Matching only "S<n>" silently drops the whole peak list on exactly
+# those datasets, which then fail the gate as "no peaks" however strong they are.
+PEAK_LABEL = re.compile(r"^[A-Za-z]{1,2}\d+$")
+
 # ANODE is run with -s4.0, so its ranked peak list stops at ~4 sigma.  An empty off-site
 # list therefore means "below 4", not "zero".
 FLOOR_MIN = 4.0
@@ -282,7 +289,7 @@ def parse_lsa(lsa, pdb, spag):
                 atoms.append((f[3], float(f[0])))
             except ValueError:
                 pass
-        elif mode == "peaks" and len(f) == 8 and f[0][0] == "S" and f[0][1:].isdigit():
+        elif mode == "peaks" and len(f) == 8 and PEAK_LABEL.match(f[0]):
             try:
                 peaks.append({"xyz": tuple(float(v) for v in f[1:4]), "h": float(f[4]),
                               "dist": float(f[6]), "near": f[7]})