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/closed_register_gate.py

@@ -50,9 +50,9 @@ WHAT THIS GATE CANNOT SEE — the residual holes, named rather than implied:
      printed as a WARNING.
   3. **A closed-sounding verdict that is not true escapes.** `PARTLY CLOSED` leads with no open word.
      This gate checks where a row FILED, never whether the verdict is honest.
-  4. **A duplicate id WITHIN one register escapes.** `OPEN-ITEMS.md` carries two unrelated findings
-     both numbered R-133 (filed as R-406). Adding that rule would fail the gate on a pre-existing
-     defect, and a registered-but-failing gate refuses every push, so it was deliberately left out.
+  4. ~~A duplicate id WITHIN one register escapes.~~ **Closed 2026-10-05 (R-416):** in `OPEN-ITEMS.md`
+     `register_shape_gate.py` RULE 3 refuses it; in `CLOSED-ITEMS.md` this gate's RULE 4 does (no duplicates
+     existed when it was added, so it was registered green).
   5. Nothing here reads audits, spikes or inventories. A finding that never reaches either register
      is invisible to this gate, as it is to `one_register_gate.py`.
 
@@ -153,6 +153,16 @@ def main():
     for rid in sorted(closed_ids & set(open_ids), key=lambda r: (int(re.sub(r"\D", "", r)), r)):
         convicted.append((open_ids[rid], rid, "", "has a row in BOTH registers"))
 
+    # RULE 4 — a duplicate id WITHIN CLOSED-ITEMS.md (2026-10-05, R-416). The open register's duplicates are
+    # register_shape_gate.py's RULE 3; this file had no such rule, so two closed rows under one id (the R-133/R-406
+    # shape) would make `git show` of "the row that closed R-n" ambiguous. Suffixed ids (R-88a, R-88b) are distinct.
+    first_seen = {}
+    for n, rid, _, _ in rows(CLOSED):
+        if rid in first_seen:
+            convicted.append((n, rid, "", "CLOSED-ITEMS.md has this id twice (first at line %d)" % first_seen[rid]))
+        else:
+            first_seen[rid] = n
+
     # RULE 3 — a finished row left in the OPEN register (2026-10-03)
     finished_in_open = []
     for n, rid, columns, cells, _ in register_table.rows(OPEN):