Add cache-safe deploy smoke checks for unstable releases

tests/e2e/cache-upgrade-smoke.spec.ts

@@ -0,0 +1,56 @@
+import { expect, test } from "@playwright/test";
+
+test("reload after deploy upgrade picks latest hashed bundle without manual cache clear", async ({
+  page,
+}) => {
+  let activeVersion = "v1";
+
+  await page.route("**/cache-upgrade-smoke/index.html", async (route) => {
+    const html = `<!doctype html>
+<html>
+  <head>
+    <meta charset=\"utf-8\" />
+    <title>Cache Upgrade Smoke</title>
+    <script src=\"/cache-upgrade-smoke/app.${activeVersion}.js\"></script>
+  </head>
+  <body>
+    <div id=\"app\">cache-upgrade-smoke</div>
+  </body>
+</html>`;
+
+    await route.fulfill({
+      status: 200,
+      contentType: "text/html",
+      headers: {
+        "cache-control": "no-cache",
+      },
+      body: html,
+    });
+  });
+
+  await page.route("**/cache-upgrade-smoke/app.*.js", async (route) => {
+    const requestUrl = new URL(route.request().url());
+    const filename = requestUrl.pathname.split("/").pop() ?? "";
+
+    await route.fulfill({
+      status: 200,
+      contentType: "application/javascript",
+      headers: {
+        "cache-control": "public, max-age=31536000, immutable",
+      },
+      body: `window.__cacheUpgradeBundle = ${JSON.stringify(filename)};`,
+    });
+  });
+
+  await page.goto("/cache-upgrade-smoke/index.html");
+  await expect
+    .poll(() => page.evaluate(() => (window as any).__cacheUpgradeBundle))
+    .toBe("app.v1.js");
+
+  activeVersion = "v2";
+
+  await page.reload();
+  await expect
+    .poll(() => page.evaluate(() => (window as any).__cacheUpgradeBundle))
+    .toBe("app.v2.js");
+});