migrate CRA to Next.js 16 + React 19 + TypeScript + Tailwind v4

- replace CRA scaffold with Next.js static export config
- add app router pages: home, homelab, archive
- add components: Nav, Footer, Hero, Skills, ProjectCard, ThemeScript
- add ThemeContext for dark mode with FOUC prevention
- add data layer: projects.ts, services.ts
- update .gitignore for Next.js (ignore .next/, out/, next-env.d.ts)
- add docs: handoff plan, homelab decisions, style reference

next.config.ts

@@ -0,0 +1,11 @@
+import type { NextConfig } from "next";
+
+const nextConfig: NextConfig = {
+  output: "export",
+  trailingSlash: true,
+  images: {
+    unoptimized: true,
+  },
+};
+
+export default nextConfig;