burn-down Part B: 14 small rows fixed and closed across four repos (306 -> 292); no :latest in the hub build; gate list pinned; closed-id duplicates refused; R-262 subset pinned

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS

scripts/test_gate_decoys.py

@@ -25,6 +25,7 @@ Run from the repo root:  python3 scripts/test_gate_decoys.py
 Exit 0 all decoys rejected · 1 a decoy passed (a live hole).
 """
 import io
+import re
 import json
 import os
 import shutil
@@ -217,6 +218,20 @@ decoy("closed-register/unreadable-row", "closed_register_gate.py",
       append_to(os.path.join(ROOT, "documentation", "backlog", "CLOSED-ITEMS.md"),
                 u"\n| **R-905** | A row with no state cell at all. |\n"))
 
+# --- closed-register RULE 4 (2026-10-05, R-416): the same id twice in CLOSED-ITEMS.md ---------------
+# The id is read from the file's FIRST closed row at run time, so the decoy duplicates a real id rather than an
+# invented one that could never collide.
+def _first_closed_id():
+    for line in io.open(os.path.join(ROOT, "documentation", "backlog", "CLOSED-ITEMS.md"), encoding="utf-8"):
+        m = re.match(r"^\| \*\*(R-\d+[a-z]?)\*\* \|", line)
+        if m:
+            return m.group(1)
+
+
+decoy("closed-register/duplicate-closed-id", "closed_register_gate.py",
+      append_to(os.path.join(ROOT, "documentation", "backlog", "CLOSED-ITEMS.md"),
+                u"\n| **%s** | The same id again. | CLOSED 2026-10-05 | none |\n" % _first_closed_id()))
+
 # --- closed-register RULE 3 (2026-10-03): a FINISHED row left in the OPEN register ---------------
 # On 2026-10-03 the open register held 113 rows whose leading verdict was finished — a quarter of the
 # file. The decoy is that exact shape: a row a session closed in place and never moved. The genuine