feat(02-01): scaffold marketing site nav, hero, listings, footer

- Add scroll-behavior: smooth and scroll-margin-top to globals.css
- Create SiteNav with sticky navy bar, desktop links, mobile hamburger
- Create HeroSection with split-panel layout and next/image
- Create ListingsPlaceholder with brand navy background and gold CTA
- Create SiteFooter with license number and TODO verify comment
- Update page.tsx to compose all section components
- Install lucide-react for icons

[Rule 1 - Bug] Fixed event handlers in server components — used CSS hover classes instead

teressa-copeland-homes/src/app/globals.css

@@ -24,3 +24,11 @@ body {
   color: var(--foreground);
   font-family: Arial, Helvetica, sans-serif;
 }
+
+html {
+  scroll-behavior: smooth;
+}
+
+section[id] {
+  scroll-margin-top: 72px;
+}