feat(home): add a first-person byline under the hero search

"Built for parents, by a parent." — the one line on the page written by a
person rather than by a product.

Placed under the search rather than in the footer, which is where it would
have been true and unread. It does its work at the moment someone is deciding
whether to trust a page full of government statistics, which is the moment
they are looking at the search box.

Set apart without shouting: display face, a step down in size, and a short
brand rule in place of a bullet. No italic — Manrope ships none in the loaded
weights, so font-style would be synthesised into a slant, the same reason
.heroEmph resets it.

Deliberately the only claim of its kind on the page. Every other trust signal
here is about the data's provenance and is checkable against the DfE and
Ofsted; this one is about who built it, and is not. So it is stated once,
plainly, and never repeated — the opposite of the "Official & trusted" line it
now sits near, which claimed something about the site that was not true.

Measured 7.26:1 in the light theme and 8.86:1 in dark.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

nextjs-app/components/HomeView.module.css

@@ -189,6 +189,43 @@
   }
 }
 
+/*
+ * The one line in the first person, so it is set apart from the marketing copy
+ * around it without shouting: display face, a step down in size, and a short
+ * brand rule instead of a bullet or an emoji.
+ *
+ * No italic — Manrope ships no italic in the loaded weights, so font-style
+ * would be synthesised into a slant. Same reason .heroEmph sets font-style
+ * back to normal.
+ */
+.heroByline {
+  display: flex;
+  align-items: center;
+  gap: 0.55rem;
+  margin: 1.25rem 0 0;
+  font-family: var(--font-display);
+  font-size: var(--step--1);
+  font-weight: 500;
+  font-style: normal;
+  color: var(--text-secondary);
+}
+
+.heroByline::before {
+  content: '';
+  flex: 0 0 auto;
+  width: 1.25rem;
+  height: 2px;
+  border-radius: 1px;
+  background: var(--brand);
+}
+
+@media (max-width: 640px) {
+  .heroByline {
+    margin-top: 1rem;
+    font-size: var(--step--2);
+  }
+}
+
 .heroEyebrow {
   display: inline-flex;
   align-items: center;