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

eslint.config.mjs

@@ -0,0 +1,18 @@
+import { defineConfig, globalIgnores } from "eslint/config";
+import nextVitals from "eslint-config-next/core-web-vitals";
+import nextTs from "eslint-config-next/typescript";
+
+const eslintConfig = defineConfig([
+  ...nextVitals,
+  ...nextTs,
+  // Override default ignores of eslint-config-next.
+  globalIgnores([
+    // Default ignores of eslint-config-next:
+    ".next/**",
+    "out/**",
+    "build/**",
+    "next-env.d.ts",
+  ]),
+]);
+
+export default eslintConfig;