feat(home): monospace intro text and updated hero headline

Use monospace font for the hero intro paragraph as a subtle nod to
Flexion Labs' code-centric identity. Replace the hero headline with
a more grounded, direct alternative.

Author: danielnaab

content/home.md

@@ -1,4 +1,4 @@
 ---
-hero: Public infrastructure, in the open.
+hero: What we build in the open.
 intro: Flexion Labs gathers our open source work in one place — products we steward, tools we share, and the commitment behind them.
 ---

src/design/layout.css

@@ -56,6 +56,7 @@
     max-inline-size: 22ch;
   }
   .home-hero__intro {
+    font-family: var(--font-mono);
     font-size: var(--step-1);
     color: var(--color-ink-subtle);
     max-inline-size: var(--measure-prose);