Migrate from Vite to Next.js 16 App Router

.gitignore

@@ -10,6 +10,10 @@ lerna-debug.log*
 node_modules
 dist
 dist-ssr
+.next
+out
+*.tsbuildinfo
+next-env.d.ts
 *.local
 
 # Editor directories and files

eslint.config.mjs

@@ -0,0 +1,28 @@
+import nextCoreWebVitals from 'eslint-config-next/core-web-vitals';
+import { defineConfig, globalIgnores } from 'eslint/config';
+
+export default defineConfig([
+  ...nextCoreWebVitals,
+  {
+    rules: {
+      'no-unused-vars': ['warn', { varsIgnorePattern: '^[A-Z_]' }],
+    },
+  },
+  {
+    // App-router layouts inject <link rel="stylesheet"> directly so the
+    // no-page-custom-font rule (which targets Pages router) doesn't apply.
+    files: ['src/app/layout.jsx'],
+    rules: {
+      '@next/next/no-page-custom-font': 'off',
+    },
+  },
+  globalIgnores([
+    '.next/**',
+    'out/**',
+    'build/**',
+    'dist/**',
+    'coverage/**',
+    'public/**',
+    'scripts/**',
+  ]),
+]);

jsconfig.json

@@ -0,0 +1,15 @@
+{
+  "compilerOptions": {
+    "baseUrl": ".",
+    "paths": {
+      "@/*": ["./src/*"]
+    },
+    "jsx": "preserve",
+    "module": "esnext",
+    "moduleResolution": "bundler",
+    "resolveJsonModule": true,
+    "checkJs": false
+  },
+  "include": ["src/**/*", "scripts/**/*"],
+  "exclude": ["node_modules", ".next", "dist", "out"]
+}

next.config.mjs

@@ -0,0 +1,18 @@
+/** @type {import('next').NextConfig} */
+const nextConfig = {
+  // Pin the workspace root so Turbopack does not silently pick up a stray
+  // lockfile from a parent directory during local development or CI.
+  turbopack: {
+    root: process.cwd(),
+  },
+  async rewrites() {
+    return [
+      {
+        source: '/ingest/:path*',
+        destination: 'https://us.i.posthog.com/:path*',
+      },
+    ];
+  },
+};
+
+export default nextConfig;