feat: turbostarter boilerplate

Production-ready Next.js boilerplate with:
- Runtime env validation (fail-fast on missing vars)
- Feature-gated config (S3, Stripe, email, OAuth)
- Docker + Coolify deployment pipeline
- PostgreSQL + pgvector, MinIO S3, Better Auth
- TypeScript strict mode (no ignoreBuildErrors)
- i18n (en/es), AI modules, billing, monitoring

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/web/src/app/not-found.tsx

@@ -0,0 +1,33 @@
+import { getTranslation } from "@turbostarter/i18n/server";
+import { buttonVariants } from "@turbostarter/ui-web/button";
+
+import { appConfig } from "~/config/app";
+import { pathsConfig } from "~/config/paths";
+import { BaseLayout } from "~/modules/common/layout/base";
+import { TurboLink } from "~/modules/common/turbo-link";
+
+export default async function NotFound() {
+  const { t } = await getTranslation({ ns: "common" });
+
+  return (
+    <BaseLayout locale={appConfig.locale}>
+      <main className="mx-auto flex max-w-xl flex-1 flex-col items-center justify-center gap-8">
+        <div className="flex flex-col items-center justify-center gap-4">
+          <h1 className="text-center text-4xl font-bold">
+            {t("error.notFound")}
+          </h1>
+          <p className="text-muted-foreground max-w-md text-center">
+            {t("error.resourceDoesNotExist")}
+          </p>
+        </div>
+
+        <TurboLink
+          href={pathsConfig.index}
+          className={buttonVariants({ variant: "outline" })}
+        >
+          {t("goBackHome")}
+        </TurboLink>
+      </main>
+    </BaseLayout>
+  );
+}