test(codex): align the Responses HTTP e2e to the #8507 input-item contract

Fifth and last base-red of the v3.8.49 pre-flight. #8507 (#8083) deliberately sets
`status: "completed"` on Responses input items so strict upstream validators accept
them; codex-chat-reasoning-http-e2e still asserted the pre-#8507 shape, so it failed
against intended behavior. Expectation updated with the reason inline — the assertion
is not relaxed, it now pins the current contract.

The test was never reached in the first pre-flight sweep (the run was interrupted
during the integration phase, and this file sorts after the one that failed).

tests/integration/codex-chat-reasoning-http-e2e.test.ts

@@ -271,11 +271,14 @@ test("chat completions streams Codex Responses reasoning through real route HTTP
     assert.equal(recorded[0].url, CODEX_RESPONSES_URL);
     assert.equal(recorded[0].method, "POST");
     assert.deepEqual(recorded[0].body.reasoning, { effort: "high", summary: "auto" });
+    // `status: "completed"` on input items is required by strict upstream Responses
+    // validators — added deliberately by #8507 (#8083); it is part of the contract now.
     assert.deepEqual(recorded[0].body.input, [
       {
         type: "message",
         role: "user",
         content: [{ type: "input_text", text: "What is the answer?" }],
+        status: "completed",
       },
     ]);