test: strip ambient Conductor env in memory-cache-injection hook harness

Same dev-in-Conductor leak fixed for question-preference-hook: this suite's
runHook copies process.env, so running it inside Conductor flipped the
defer-path memoryContext assertions into the [conductor] prose deny. Strip
CONDUCTOR_* so the cases characterize non-Conductor behavior. (CI is headless,
so this only bit local Conductor runs.)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

test/memory-cache-injection.test.ts

@@ -43,6 +43,11 @@ function runHook(stdin: object): { stdout: string; stderr: string; status: numbe
   env.GSTACK_STATE_ROOT = stateRoot;
   env.GSTACK_QUESTION_LOG_NO_DERIVE = '1';
   delete env.GSTACK_HOME;
+  // These cases assert the defer-path memoryContext injection. Strip ambient
+  // Conductor markers so running inside Conductor (CONDUCTOR_WORKSPACE_PATH/PORT
+  // set) doesn't flip the hook into the [conductor] prose deny instead of defer.
+  delete env.CONDUCTOR_WORKSPACE_PATH;
+  delete env.CONDUCTOR_PORT;
   const res = spawnSync(HOOK, [], {
     env,
     input: JSON.stringify({ ...stdin, cwd: fixtureCwd }),