tooling(pm): record the #15556 reproduction's engine double in the pinned ledger

`check:engine-double-contract` reported RETAINED on both write verbs for the
new test file: its fake engine routes delete()/update() through ObjectQL's own
dispatch predicates, but the pinned ledger had no row for the file, so the
coverage protected nothing. Written by `--write`, as the gate instructs.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XpTx2tbq3pZRYAdoGt6E6Y

Author: claude

scripts/engine-double-contract.pinned.json

@@ -2166,6 +2166,16 @@
       "verb": "update",
       "pinned": 1
     },
+    {
+      "file": "packages/plugins/plugin-approvals/src/subflow-hosted-approval-strand.test.ts",
+      "verb": "delete",
+      "pinned": 1
+    },
+    {
+      "file": "packages/plugins/plugin-approvals/src/subflow-hosted-approval-strand.test.ts",
+      "verb": "update",
+      "pinned": 1
+    },
     {
       "file": "packages/plugins/plugin-approvals/src/team-approver-org-screen.test.ts",
       "verb": "delete",