test(server): correct resolveShell mutation-control record in audit receipt

The '/bin/bash' fallback control fails three retained rows in the
focused 'shell fallback' selection (linux unset, empty SHELL, missing
absolute path), not only the linux unset row; the earlier 'breaks
nothing else' claim in the receipt was wrong. Re-ran the control on
the published candidate tree (3 failed, 5 passed; restored byte-exact,
sha256 335fd533..., rerun 8/8) and recorded the exact failure set.
Resolves the Greptile P2 on the receipt evidence.

doc/plans/2026-10-17-workspace-runtime-resolveshell-test-audit.md

@@ -30,10 +30,18 @@ Node 25.9.0, isolated checkout with `pnpm install --filter @paperclipai/server..
 1. Baseline (before edit): 9/9 passed.
 2. Candidate (darwin row deleted): 8/8 passed.
 3. Control: temporarily changed the production fallback arm to
-   `"/bin/bash"`. The retained linux row failed at its exact assertion
+   `"/bin/bash"` and reran the same focused selection (re-verified
-   (`expected '/bin/bash' to be '/bin/sh'`), proving the retained row
+   2026-10-17). Exactly three rows failed at the same assertion shape
-   carries the deleted row's failure sensitivity. The non-win32 arm's
+   (`expected '/bin/bash' to be '/bin/sh'`): the retained linux unset
-   mutation also breaks nothing else in the selected run.
+   row (the deleted darwin row's keeper), the empty-`SHELL` row, and
+   the missing-absolute-path row. The win32 rows and the set-`SHELL`
+   rows still passed (3 failed, 5 passed). This proves the retained
+   linux row carries the deleted row's failure sensitivity; it also
+   shows the same non-win32 fallback value is observed by the
+   empty-`SHELL` and missing-absolute-path rows, so that value keeps
+   multiple guards after this change. An earlier draft of this receipt
+   wrongly said the mutation "breaks nothing else" in the selected run;
+   that claim is corrected here (Greptile review finding, PR #16639).
 4. Production restored byte-exact (sha256
    `335fd5332b4242ab0ff2a565323e27db48a69ddfb7bbd8d913e5148f79ff961b`
    before and after), rerun: 8/8 passed.