feat: migrate landing page to TypeScript and fix auth cookies

- Migrate all apps/website components from JS/JSX to TypeScript/TSX
- Add blog pages (layout, listing, slug) in TypeScript
- Add tsconfig.json and tailwind.config.mjs to website
- Fix cookie domain handling in vite/App.tsx (set .useautumn.com in prod)
- Update auth.ts, afterSessionCreated, afterSessionDeleted

Made-with: Cursor

apps/website/tailwind.config.mjs

@@ -0,0 +1,7 @@
+import typography from "@tailwindcss/typography";
+
+const config = {
+  plugins: [typography],
+};
+
+export default config;