docs: update landing <title> to match h1 tagline

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

Author: beautyfree

docs/index.html

@@ -30,7 +30,7 @@
       name="twitter:image"
       content="https://raw.githubusercontent.com/beautyfree/skiller-skills-desktop-manager/main/docs/images/og-skiller.png"
     />
-    <title>Skiller — download</title>
+    <title>Skiller — Your skills HQ for every SKILL.md</title>
     <link rel="icon" type="image/png" sizes="32x32" href="favicon-32x32.png" />
     <link rel="icon" type="image/png" sizes="16x16" href="favicon-16x16.png" />
     <link rel="apple-touch-icon" sizes="180x180" href="apple-touch-icon.png" />