Add theme toggle, hero snippet, and reorganize homepage components

- Set up next-themes with a light/dark toggle in the header and move all
  sections onto theme tokens; dark mode stays pure black
- Replace the hero terminal line with the AI Elements Snippet component
- Restructure components into layout/, sections/, and shared/ with
  site-wide config in lib/site.ts

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

app/page.tsx

@@ -1,23 +1,23 @@
-import { Cta } from '@/components/site/cta';
-import { Features } from '@/components/site/features';
-import { Footer } from '@/components/site/footer';
-import { Hero } from '@/components/site/hero';
-import { LogoCloud } from '@/components/site/logo-cloud';
-import { Navbar } from '@/components/site/navbar';
-import { Stats } from '@/components/site/stats';
+import { SiteFooter } from '@/components/layout/site-footer';
+import { SiteHeader } from '@/components/layout/site-header';
+import { CtaSection } from '@/components/sections/cta-section';
+import { FeaturesSection } from '@/components/sections/features-section';
+import { HeroSection } from '@/components/sections/hero-section';
+import { LogosSection } from '@/components/sections/logos-section';
+import { StatsSection } from '@/components/sections/stats-section';
 
 export default function Home() {
   return (
     <>
-      <Navbar />
-      <main>
-        <Hero />
-        <LogoCloud />
-        <Features />
-        <Stats />
-        <Cta />
+      <SiteHeader />
+      <main id="top">
+        <HeroSection />
+        <LogosSection />
+        <FeaturesSection />
+        <StatsSection />
+        <CtaSection />
       </main>
-      <Footer />
+      <SiteFooter />
     </>
   );
 }