feat(auth): wire AuthProvider + RequireAuth into app shell

src/App.tsx

@@ -13,6 +13,8 @@ import { Acks } from "@/pages/Acks";
 import { Batches } from "@/pages/Batches";
 import { BatchDiff } from "@/pages/BatchDiff";
 import Inbox from "@/pages/Inbox";
+import { Login } from "@/pages/Login";
+import { RequireAuth } from "@/auth/RequireAuth";
 
 function NotFound() {
   return (
@@ -27,7 +29,14 @@ export default function App() {
   return (
     <DrillStackProvider>
       <Routes>
-        <Route element={<Layout />}>
+        {/* /login sits OUTSIDE the auth-gated Layout so an
+            unauthenticated operator can reach the sign-in screen. */}
+        <Route path="/login" element={<Login />} />
+        {/* Every other route inherits the auth gate via RequireAuth
+            wrapping the Layout outlet. Authenticated operators see
+            the full app; unauthenticated ones are bounced back here
+            with `?next=<current>`. */}
+        <Route element={<RequireAuth><Layout /></RequireAuth>}>
           <Route index element={<Dashboard />} />
           <Route path="claims" element={<Claims />} />
           <Route path="remittances" element={<Remittances />} />