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>

packages/analytics/web/src/providers/posthog/index.tsx

@@ -0,0 +1,71 @@
+"use client";
+
+import dynamic from "next/dynamic";
+import posthog from "posthog-js";
+import { PostHogProvider } from "posthog-js/react";
+import { Suspense } from "react";
+
+import { env } from "./env";
+
+import type { AnalyticsProviderClientStrategy } from "@turbostarter/analytics";
+
+const PageView = dynamic(
+  () => import("./page-view").then((mod) => mod.PageView),
+  {
+    ssr: false,
+  },
+);
+
+const isValidPosthogConfig =
+  env.NEXT_PUBLIC_POSTHOG_KEY &&
+  env.NEXT_PUBLIC_POSTHOG_KEY !== "notyet" &&
+  env.NEXT_PUBLIC_POSTHOG_HOST.startsWith("http");
+
+if (typeof window !== "undefined" && isValidPosthogConfig) {
+  posthog.init(env.NEXT_PUBLIC_POSTHOG_KEY!, {
+    api_host: env.NEXT_PUBLIC_POSTHOG_HOST,
+    person_profiles: "always",
+    capture_pageview: false,
+    disable_external_dependency_loading: true,
+    disable_session_recording: true,
+  });
+}
+
+export const { Provider, track, identify, reset } = {
+  Provider: ({ children }) => {
+    // Skip PostHog wrapper entirely when not configured
+    if (!isValidPosthogConfig) {
+      return <>{children}</>;
+    }
+
+    return (
+      <PostHogProvider client={posthog}>
+        {children}
+        <Suspense fallback={null}>
+          <PageView />
+        </Suspense>
+      </PostHogProvider>
+    );
+  },
+  track: (event, properties) => {
+    if (typeof window === "undefined") {
+      return;
+    }
+
+    posthog.capture(event, properties);
+  },
+  identify: (userId, traits) => {
+    if (typeof window === "undefined") {
+      return;
+    }
+
+    posthog.identify(userId, traits);
+  },
+  reset: () => {
+    if (typeof window === "undefined") {
+      return;
+    }
+
+    posthog.reset();
+  },
+} satisfies AnalyticsProviderClientStrategy;