site: one playground - the nav API entry is labeled API

With /playground live, the nav advertised two different pages as
playgrounds: 'API playground' (/api, the form that generates
snippets) and 'Playground' (/playground, the TS editor). The /api
entry is now labeled 'API', matching the page's own headline.

Author: ronaldtse

src/layouts/Base.astro

@@ -44,7 +44,7 @@ const navItems: NavItem[] = [
   {
     label: "Developers",
     children: [
-      { href: "/api", label: "API playground" },
+      { href: "/api", label: "API" },
       { href: "https://api.interscript.org/docs", label: "API reference" },
       { href: "/status", label: "Status" },
     ],
@@ -86,7 +86,7 @@ const drawerGroups: Array<{ label: string; links: NavLink[] }> = [
   {
     label: "Developers",
     links: [
-      { href: "/api", label: "API playground" },
+      { href: "/api", label: "API" },
       { href: "https://api.interscript.org/docs", label: "API reference" },
       { href: "/status", label: "Status" },
     ],

src/pages/use-cases.astro

@@ -158,7 +158,7 @@ const useCases: UseCase[] = [
         need. Open an issue on GitHub to discuss your scenario.
       </p>
       <div class="cta-actions">
-        <a class="btn btn-accent" href="/api">Try the API playground →</a>
+        <a class="btn btn-accent" href="/api">Try the API →</a>
         <a
           class="btn btn-ghost"
           href="https://github.com/interscript/interscript-ruby/discussions"