feat(ci): stamp build metadata and validate footer version hash

e2e/smoke.pw.ts

@@ -1,10 +1,13 @@
 import { expect, test } from "@playwright/test"
 
+const BUILD_INFO_PATTERN = /Build v\S+ \+sha\.[a-z0-9]{5,7}/i
+
 test("smoke", async ({ page }, testInfo) => {
   await page.goto("/")
 
   if (testInfo.project.name === "web-chromium") {
     await expect(page.getByRole("heading", { name: /your next\.js cms frontend/i })).toBeVisible()
+    await expect(page.getByText(BUILD_INFO_PATTERN)).toBeVisible()
     return
   }
 
@@ -12,6 +15,7 @@ test("smoke", async ({ page }, testInfo) => {
 
   if (await dashboardHeading.isVisible({ timeout: 2000 })) {
     await expect(dashboardHeading).toBeVisible()
+    await expect(page.getByText(BUILD_INFO_PATTERN)).toBeVisible()
     return
   }