fix: scope workspace registry smoke cleanup

backend/test/workspaces-migrate-legacy.test.ts

@@ -1,3 +1,4 @@
+import { execFileSync } from "node:child_process";
 import { existsSync, readFileSync, rmSync, writeFileSync } from "node:fs";
 import { mkdtemp } from "node:fs/promises";
 import { tmpdir } from "node:os";
@@ -100,3 +101,13 @@ test("declares a durable isolated registry volume and only read-only Git credent
   expect(smoke).toContain('"degraded":true');
   expect(smoke).toContain('core_remote="/fixtures/remote.git"');
 });
+
+test("workspace registry smoke image cleanup is scoped to the per-run image identity", () => {
+  const output = execFileSync("bash", ["scripts/workspace-registry-smoke.sh"], {
+    cwd: new URL("../..", import.meta.url),
+    env: { ...process.env, WORKSPACE_REGISTRY_SMOKE_SELF_TEST: "image-cleanup-identity" },
+    encoding: "utf8",
+  });
+
+  expect(output).toContain("workspace registry smoke image cleanup identity self-test passed");
+});