Promote to UAT: GRO-2094 React bootstrap error instrumentation (#45)

Co-authored-by: The Dogfather <20+gb_dogfather@noreply.git.farh.net>
Co-committed-by: The Dogfather <20+gb_dogfather@noreply.git.farh.net>

src/portal/CustomerPortal.tsx

@@ -241,13 +241,31 @@ export function CustomerPortal() {
 
   const avatarInitials = (clientName.split(" ")[0] || "G").charAt(0).toUpperCase();
 
+  // Show a loading state while the SSO bridge is in progress. The portal chrome
+  // and its sections (e.g. Dashboard) assume a session is established and run
+  // their own auth guards — rendering them before the bridge resolves triggers
+  // a redirect to /login from `Dashboard.tsx`'s `!sessionId` check, breaking the
+  // post-sign-in flow. Once `initComplete` is true we know whether a session was
+  // established and can render the correct branch. See GRO-2099.
+  if (!initComplete) {
+    return (
+      <div
+        className="min-h-screen flex items-center justify-center bg-[#faf8f5]"
+        role="status"
+        aria-live="polite"
+      >
+        <div className="text-stone-500 text-sm">Loading…</div>
+      </div>
+    );
+  }
+
   // After init completes, redirect unauthenticated users to /login and staff to /admin.
   // The portal chrome must NEVER be visible to users without a valid client session.
   // For client dev users, we stay on the portal even if session is null — the dev-session
   // response may not have id set immediately, or there may be timing issues with the
   // session state. Dev users are verified via localStorage and the dev-session flow.
   // SSO customers are recognised by portalSessionId (set by the Better Auth bridge).
-  if (initComplete && !session && !portalSessionId) {
+  if (!session && !portalSessionId) {
     if (authError) {
       // GRO-1867: graceful 404 fallback — authenticated user has no client row.
       return (