fix(a11y): skip-link no longer blocks logo click outside focus

The "Skip to content" link is `position: fixed; top-2 left-2 z-[100]`
on every authenticated page. Even with `opacity-0` it still occupied
its bounding box, so a mouse click on the desktop logo (also at the
top-left corner) sometimes hit the invisible link instead.

Fix: keep the visual treatment (opacity, focus styles) but combine
`pointer-events-none` + `-translate-y-full` in the unfocused state so
the element neither receives clicks nor occupies any visible space.
On focus, both modifiers reverse — the link slides into view and
becomes interactive again. Existing keyboard flow is unchanged: Tab
focuses the link, the focus ring + translucent slide-in is preserved.

Tests: extend `e2e/a11y.spec.ts` with a Playwright check that the
desktop logo is clickable from its centre on the dashboard and the
URL stays at "/".

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

e2e/a11y.spec.ts

@@ -110,4 +110,43 @@ test.describe("axe-core authenticated surfaces", () => {
       expect(blocking).toHaveLength(0);
     });
   }
+
+  // The keyboard-only "skip to content" link is fixed at the top-left
+  // corner of every authenticated page. Marc reported it intercepting
+  // logo clicks in v1.4.14 — the fix combines `pointer-events-none`
+  // with `-translate-y-full` so the element sits offscreen until
+  // focused. Regression guard: with no keyboard focus, the logo's own
+  // bounding box must accept the click.
+  test("skip-link does not block logo click outside focus", async ({
+    page,
+  }) => {
+    await page.goto("/", { waitUntil: "domcontentloaded" });
+    await page.waitForLoadState("networkidle");
+
+    // Find the desktop sidebar logo link — `<Logo>` is rendered inside
+    // a `<Link href="/">` and the only logo at the absolute top-left
+    // of the layout. We resolve it by role / accessible name to avoid
+    // brittle selectors.
+    const logoLink = page
+      .locator("a[href='/']")
+      .filter({ hasText: "HealthLog" })
+      .first();
+    await expect(logoLink).toBeVisible();
+
+    const logoBox = await logoLink.boundingBox();
+    expect(logoBox).not.toBeNull();
+    if (!logoBox) return;
+
+    // Click the centre of the logo. If the skip-link is intercepting
+    // pointer events, Playwright's auto-waiting click would either time
+    // out or report the wrong element. The defensive `force: false`
+    // (default) ensures we go through the full hit-test pipeline.
+    await logoLink.click({
+      position: { x: logoBox.width / 2, y: logoBox.height / 2 },
+    });
+
+    // Logo points at "/", so we either stay on "/" or get a no-op
+    // reload. Either way the URL must remain on the dashboard.
+    await page.waitForURL(/\/$/);
+  });
 });

src/components/layout/auth-shell.tsx

@@ -114,9 +114,17 @@ export function AuthShell({ children }: { children: React.ReactNode }) {
       {showUnlockNotifier && user?.id ? (
         <AchievementUnlockNotifier userId={user.id} />
       ) : null}
+      {/*
+        Keyboard-only skip link. The non-focused state has both
+        `pointer-events-none` (so a mouse click in the top-left corner
+        passes through to the logo behind it) AND `-translate-y-full`
+        (so even an accidental tap with stylus / touch can't activate
+        it). Focus restores both — the element jumps back into the
+        viewport and becomes clickable.
+      */}
       <a
         href="#main-content"
-        className="bg-primary text-primary-foreground fixed top-2 left-2 z-[100] rounded-md px-4 py-2 text-sm font-medium opacity-0 focus:opacity-100"
+        className="bg-primary text-primary-foreground fixed top-2 left-2 z-[100] -translate-y-full rounded-md px-4 py-2 text-sm font-medium opacity-0 transition-transform pointer-events-none focus:translate-y-0 focus:opacity-100 focus:pointer-events-auto"
       >
         {t("nav.skipToContent")}
       </a>