feat(confidence-engine): establish authenticated product boundary

lib/supabase/browser.js

@@ -0,0 +1,14 @@
+"use client";
+
+import { createBrowserClient } from "@supabase/ssr";
+
+export function createClient() {
+  return createBrowserClient(
+    process.env.NEXT_PUBLIC_SUPABASE_URL,
+    process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY,
+  );
+}
+
+export function magicLinkRedirectTo(origin) {
+  return `${origin}/auth/callback`;
+}