Return the AlvenX header to top while preserving Demo state

AGENTS.md

@@ -98,6 +98,11 @@ Run `pnpm brand:verify` (included in `pnpm check`/CI). In the AlvenX workspace a
 Visual changes require actual 390/900/1440px browser and resource-loading checks, comparison of
 computed header geometry to an accepted Studio, and independent checkout verification.
 
+The AlvenX wordmark is a native `data-alvenx-home` button with an accessible Back to top name.
+Apply home-navigation revision 2026-09-04.1 from the shared interface contract: true document top,
+no action when already at the top, preserved URL/history and product state, native keyboard
+activation, visible focus and immediate scrolling under reduced motion.
+
 ## Testing standards
 
 Use the layers needed by the phase:

docs/assets/alvenx-ui.css

@@ -115,6 +115,25 @@
   height: auto;
 }
 
+/* Header home-navigation revision: 2026-09-04.1 */
+.ax-product-header [data-alvenx-home] {
+  display: flex;
+  align-items: center;
+  flex: 0 0 auto;
+  width: var(--ax-product-header-wordmark-width);
+  min-height: var(--ax-control-height);
+  padding: 0;
+  border: 0;
+  border-radius: 12px;
+  background: transparent;
+  cursor: pointer;
+}
+
+.ax-product-header [data-alvenx-home]:focus-visible {
+  outline: 3px solid rgb(37 99 235 / 45%);
+  outline-offset: 4px;
+}
+
 .ax-metric-frame {
   border: 1px solid var(--ax-rule);
 }

docs/assets/provenance.json

@@ -17,7 +17,7 @@
     {
       "path": "docs/assets/alvenx-ui.css",
       "source": "foundation/brand/interface/alvenx-ui.css",
-      "sha256": "7b94510cfa9fe9eebe452481f967a9482809c5158a326842971e1d457f86daf6"
+      "sha256": "b4bc3051213c2d9a1a37af80233d0b4978941d73c5945f6a792b84271e1d5c0c"
     },
     {
       "path": "docs/assets/InstrumentSans-wdth-wght.woff2",
@@ -30,5 +30,6 @@
       "sha256": "bc29b497c4e8316b2d248322a9cea670c2f0afc24ae0eb7bbaa54e02e00eebab"
     }
   ],
-  "wordmarkAlignmentRevision": "2026-09-04.1"
+  "wordmarkAlignmentRevision": "2026-09-04.1",
+  "homeNavigationRevision": "2026-09-04.1"
 }

docs/brand.md

@@ -15,6 +15,14 @@ the subtitle-free 330×100 master, centered at 320px, followed by `<br>` and the
 `<sub>FUNCTIONAL REGRESSION EVIDENCE</sub>` line before the H1. The Demo reuses that SVG at
 160px inside `.ax-product-header`.
 
+Header activation follows home-navigation revision **2026-09-04.1**: wrap the wordmark in a
+native `type="button"` with `data-alvenx-home` and the accessible name `AlvenX — Back to top`.
+Use the canonical CSS reset/focus rules. Pointer, Enter and Space return the current document
+to its true top; activation at the top is a no-op. Preserve the complete URL/history, current
+view, results and running work. Reduced motion scrolls immediately; other activation is smooth.
+The implementation lives in `src/demo/public/index.html` and `app.js`; the real-browser
+regression lives in `tests/playwright/demo.spec.ts`.
+
 The shared CSS controls the static four-layer background, typography, glass surfaces and header
 geometry. Product CSS may arrange the case/run workflow and add visible focus/reduced-motion
 behavior; it must not override approved header values or redraw the logo.

harness/context/03-brand-verifiable-demo.md

@@ -183,3 +183,31 @@ Ten current computed header properties match the preserved accepted Studio refer
 CSS is unchanged. Exact PR/main integration receipts are retained in
 `.workspace/audits/reprolock-english-demo-20260904/` in the parent AlvenX workspace and the PR,
 so recording the final merge does not change the tested source tree.
+
+## AlvenX header activation follow-up — 2026-09-04
+
+English PR #4 merged as `5b16d22`; both its PR and main Node 22/24 CI jobs passed and the
+fixed D checkout was clean before the owner added uniform logo activation through the brand
+coordinating task. Branch `codex/alvenx-header-home` implements that scoped request with one writer.
+Baseline `pnpm brand:verify` and `pnpm test:browser` passed (4/4) before editing.
+
+The native `AlvenX — Back to top` button wraps the unchanged wordmark. Its click handler returns
+immediately at scrollY zero, otherwise scrolls the current document to top zero while preserving
+scrollX; reduced motion uses `instant`, otherwise `smooth`. No navigation or execution state is
+changed. The exact approved canonical CSS now includes the button reset and visible focus rules;
+its SHA-256 is `b4bc3051213c2d9a1a37af80233d0b4978941d73c5945f6a792b84271e1d5c0c`.
+Provenance records independent home-navigation revision `2026-09-04.1`.
+
+Actual `pnpm check` passed 80/80 unit/process and 4/4 browser tests. Existing browser coverage now
+checks pointer, Enter and Space under normal and reduced motion, true document top, activation
+at the top, and preservation of the selected saved result, export, expanded source, URL/hash,
+history and document lifetime. The three widths retain the canonical geometry and 160px wordmark;
+the button has visible keyboard focus. All historical and recorded evidence verifiers passed.
+`pnpm package:smoke` passed (108 files / 370,413 bytes before this receipt update).
+Shared brand validation passed 22 assets, five README headers and five header-navigation contracts;
+workspace validation passed five independent repositories. Independent read-only review passed.
+
+The independent source export and exact PR/main CI integration receipts are recorded after the
+source commit in `.workspace/audits/reprolock-header-home-20260904/` in the parent workspace and
+the PR. This follow-up preserves all raw experiments and screenshots and does not repeat or
+reclassify the historical 20+20 experiment. Product stage remains `SPIKE_CONDITIONAL`.

plans/03-brand-verifiable-demo.md

@@ -105,3 +105,18 @@ merge receipts are retained in the PR and local audit without changing the teste
 - [x] English copy, documentation and current screenshot.
 - [x] Browser/resource/layout, independent-export and configured engineering checks.
 - [x] Independent review; exact-head PR/merge receipts close integration in the PR/local audit.
+
+## AlvenX header activation — 2026-09-04
+
+After English PR #4 merged as `5b16d22`, the owner requested the same header-logo activation
+across all AlvenX interfaces through the coordinating brand task. ReproLock remains under one
+writer in the fixed D checkout, branch `codex/alvenx-header-home`. Baseline `pnpm brand:verify`
+and `pnpm test:browser` passed (4/4) before editing.
+
+Use the canonical native `data-alvenx-home` button and shared CSS revision 2026-09-04.1.
+Activation returns the document to its true top, does nothing at the top, respects reduced
+motion and preserves the URL/history, current view, results and running work. Keep the existing
+160px wordmark and header geometry. Update the existing browser coverage for pointer/keyboard
+activation and retained state, verify the canonical assets and independent export, then review,
+submit, follow both Node CI jobs, merge and synchronize D main. Preserve the English delivery
+and all historical evidence; this changes interface behavior only.

scripts/verify-brand.mjs

@@ -10,6 +10,7 @@ export async function verifyBrand(root) {
   assert.equal(provenance.schemaVersion, 1);
   assert.equal(provenance.brandRevision, "2026-08-24.1");
   assert.equal(provenance.interfaceRevision, "2026-08-25.2");
+  assert.equal(provenance.homeNavigationRevision, "2026-09-04.1");
   const names = [
     "alvenx-wordmark.svg",
     "alvenx-monogram.svg",
@@ -43,6 +44,7 @@ export async function verifyBrand(root) {
     readmes: readmes.length,
     brandRevision: provenance.brandRevision,
     interfaceRevision: provenance.interfaceRevision,
+    homeNavigationRevision: provenance.homeNavigationRevision,
   };
 }
 

src/demo/public/app.js

@@ -25,6 +25,15 @@ const results = {
   "browser-runtime-error": "Browser runtime error",
 };
 
+document.querySelector("[data-alvenx-home]").addEventListener("click", () => {
+  if (window.scrollY === 0) return;
+  window.scrollTo({
+    top: 0,
+    left: window.scrollX,
+    behavior: window.matchMedia("(prefers-reduced-motion: reduce)").matches ? "instant" : "smooth",
+  });
+});
+
 async function control(action) {
   const response = await fetch(`/api/${action}`, {
     method: "POST",

src/demo/public/index.html

@@ -13,7 +13,7 @@
   <body class="ax-canvas">
     <a class="skip-link" href="#main">Skip to verification workspace</a>
     <header class="ax-product-header">
-      <img class="ax-product-header__wordmark" src="/assets/alvenx-wordmark.svg" width="330" height="100" alt="AlvenX">
+      <button type="button" data-alvenx-home aria-label="AlvenX — Back to top"><img class="ax-product-header__wordmark" src="/assets/alvenx-wordmark.svg" width="330" height="100" alt="AlvenX"></button>
       <nav aria-label="Product"><a href="#main">ReproLock</a><span class="local-tag">LOCAL</span></nav>
     </header>
     <main id="main">

tests/playwright/demo.spec.ts

@@ -33,6 +33,9 @@ test("Demo loads standalone brand resources and preserves canonical responsive h
   page.on("pageerror", (error) => errors.push(error.message));
   await page.goto(demo.address);
   await expect(page.locator("html")).toHaveAttribute("lang", "en");
+  const home = page.getByRole("button", { name: "AlvenX — Back to top", exact: true });
+  await expect(home).toHaveAttribute("type", "button");
+  await expect(home).toHaveAttribute("data-alvenx-home", "");
   await expect(page.locator("#history-verification")).toContainText("frozen inputs verified");
   for (const width of [390, 900, 1440]) {
     await page.setViewportSize({ width, height: 1000 });
@@ -70,6 +73,8 @@ test("Demo loads standalone brand resources and preserves canonical responsive h
   expect(
     await page.locator("#start").evaluate((element) => getComputedStyle(element).outlineStyle),
   ).toBe("solid");
+  await home.focus();
+  expect(await home.evaluate((element) => getComputedStyle(element).outlineStyle)).toBe("solid");
   await page.emulateMedia({ reducedMotion: "reduce" });
   expect(await page.evaluate(() => getComputedStyle(document.documentElement).scrollBehavior)).toBe(
     "auto",
@@ -85,7 +90,7 @@ test("Demo loads standalone brand resources and preserves canonical responsive h
   expect(errors).toEqual([]);
 });
 
-test("startup failure has zero current observations and can be reopened without reloading", async ({
+test("saved startup failure survives header home activation without navigation or reloading", async ({
   page,
 }) => {
   await page.goto(demo.address);
@@ -100,6 +105,39 @@ test("startup failure has zero current observations and can be reopened without
   await expect(page.locator("#timing")).toContainText("Not re-executed");
   const exported = await page.request.get(`${demo.address}/api/export/${id}`);
   expect((await exported.json()).schemaVersion).toBe(1);
+
+  await page.getByRole("link", { name: "ReproLock", exact: true }).click();
+  await page.getByText("Inspect the frozen test", { exact: true }).click();
+  const retainedState = () =>
+    page.evaluate(() => ({
+      url: location.href,
+      historyLength: history.length,
+      historyState: history.state,
+      documentStarted: performance.timeOrigin,
+      run: document.querySelector(".run-panel")?.textContent,
+      export: document.querySelector("#export")?.getAttribute("href"),
+      sourceOpen: document.querySelector(".source-detail")?.hasAttribute("open"),
+    }));
+  const before = await retainedState();
+  expect(before.url).toContain("#main");
+  expect(before.sourceOpen).toBe(true);
+  const home = page.getByRole("button", { name: "AlvenX — Back to top", exact: true });
+  for (const reducedMotion of ["no-preference", "reduce"] as const) {
+    await page.emulateMedia({ reducedMotion });
+    for (const activation of ["click", "Enter", "Space"]) {
+      await page.evaluate(() =>
+        window.scrollTo({ top: document.documentElement.scrollHeight, behavior: "instant" }),
+      );
+      await expect.poll(() => page.evaluate(() => window.scrollY)).toBeGreaterThan(0);
+      if (activation === "click") await home.click();
+      else await home.press(activation);
+      await expect.poll(() => page.evaluate(() => window.scrollY)).toBe(0);
+      expect(await retainedState()).toEqual(before);
+    }
+    await home.click();
+    expect(await page.evaluate(() => window.scrollY)).toBe(0);
+    expect(await retainedState()).toEqual(before);
+  }
 });
 
 test("concurrent controls admit exactly one configured run and reject foreign control requests", async ({