fix: align OpenAI cache affinity and use uuidv7 session ids

packages/ai/test/openai-codex-cache-affinity-e2e.test.ts

@@ -0,0 +1,36 @@
+import { describe, expect, it } from "vitest";
+import { getModel } from "../src/models.js";
+import { complete } from "../src/stream.js";
+import type { Context } from "../src/types.js";
+import { resolveApiKey } from "./oauth.js";
+
+const codexToken = await resolveApiKey("openai-codex");
+
+describe("openai-codex cache affinity e2e", () => {
+	it.skipIf(!codexToken)("handles SSE requests with aligned cache-affinity identifiers", async () => {
+		const model = getModel("openai-codex", "gpt-5.3-codex");
+		const sessionId = "0195d6e4-4cf9-7f44-a2d8-f8f7f49ee9d3";
+		const context: Context = {
+			systemPrompt: "You are a helpful assistant. Reply exactly as requested.",
+			messages: [
+				{
+					role: "user",
+					content: "Reply with exactly: cache affinity e2e success",
+					timestamp: Date.now(),
+				},
+			],
+		};
+
+		const response = await complete(model, context, {
+			apiKey: codexToken,
+			sessionId,
+			transport: "sse",
+		});
+
+		expect(response.stopReason, response.errorMessage).not.toBe("error");
+		expect(response.errorMessage).toBeUndefined();
+		expect(response.content.map((block) => (block.type === "text" ? block.text : "")).join("")).toContain(
+			"cache affinity e2e success",
+		);
+	});
+});