feat(web): TanStack Query hooks + session-guarded routes

Installs @tanstack/react-query and react-router-dom; adds typed query
hooks (useMe, useObjectsPage, useObject, useFieldDefinitions, useLogin,
useLogout), a QueryClient+MemoryRouter test render helper, and
RequireAuth — a layout route that blocks unauthenticated access and
redirects to /login. All 7 tests pass, typecheck/lint/build clean.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

web/src/test/render.tsx

@@ -0,0 +1,16 @@
+import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
+import { render } from "@testing-library/react";
+import type { ReactElement } from "react";
+import { MemoryRouter } from "react-router-dom";
+
+import "../i18n";
+
+export function renderApp(ui: ReactElement, { route = "/" } = {}) {
+  const qc = new QueryClient({ defaultOptions: { queries: { retry: false } } });
+
+  return render(
+    <QueryClientProvider client={qc}>
+      <MemoryRouter initialEntries={[route]}>{ui}</MemoryRouter>
+    </QueryClientProvider>,
+  );
+}