chore: drop two exports nothing reaches

The dead-code gate has been red on this branch since the sharing refusal
contracts landed. Neither name is new and neither was noticed, because
knip is not in the local gate.

consentRequiredResponse lost its last caller when every delegable route
started sharing one 403 description through recordRefusal(); the AI
consent sentence it wrapped is still used and stays, with a note at the
constant saying why there is no response object beside it any more.
mutateThenRestore was written with the sharing security fixtures and has
never been called.

No ignore entries: an export with no consumer is the thing the gate is
for.

tests/fixtures/v137/security-principals.ts

@@ -60,19 +60,3 @@ export const SECURITY_PRINCIPALS = {
     job: { id: "job-owner-idempotency", origin: "owner-request" },
   },
 } as const satisfies Record<string, SecurityPrincipalFixture>;
-
-export async function mutateThenRestore<T>(
-  mutate: () => Promise<T>,
-  restore: (result: T) => Promise<void>,
-): Promise<T> {
-  let result: T | undefined;
-  let completed = false;
-
-  try {
-    result = await mutate();
-    completed = true;
-    return result;
-  } finally {
-    if (completed) await restore(result as T);
-  }
-}