style: retitle the home intro link to "Why and how"

The About page leads with Motivation then How it works, so the link
now reflects both halves rather than just the mechanics.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: kt3k

src/index.page.ts

@@ -192,7 +192,7 @@ export default function (data: Lume.Data): string {
 </script>`;
 
   const intro = `<div class="mb-10 border-b border-rule pb-8">
-      <p class="m-0 text-lg leading-snug text-ink-soft">A daily, LLM-written digest of selected git repositories. <a class="font-semibold text-accent no-underline hover:underline" href="/about">How it works →</a></p>
+      <p class="m-0 text-lg leading-snug text-ink-soft">A daily, LLM-written digest of selected git repositories. <a class="font-semibold text-accent no-underline hover:underline" href="/about">Why and how →</a></p>
     </div>`;
 
   return `${intro}<div>${cards.join("\n")}</div>${script}`;