feat(frontend): app do tenant, dashboard ao vivo, fluxo de login multi-tenant

Corrige um gap real: o login sempre mandava pra /platform mesmo pra
usuarios sem role de plataforma, sem nunca chamar /auth/tenants ou
select-tenant. Agora POST /api/post-login decide o destino server-side
(plataforma / tenant unico / seletor com >1 tenant) antes de redirecionar,
trocando o access token quando necessario sem nunca expor token ao client.

Adiciona GET /reports/dashboard (secao 162) e a tela /app correspondente
— chamadas/agentes/TME/TMA/rates ao vivo, "consumo do plano" e "valor
estimado" seguindo a mesma disciplina de honestidade (null > numero
inventado) do dashboard de plataforma.

Shell (sidebar/topbar/drawer mobile) extraido pra components/shell,
compartilhado entre os menus Platform e Tenant (secao 168-169) via
wrappers client-only por area — corrige de quebra um erro real de
serializacao RSC (passar NavSection[] com icones como prop de Server
Component pra Client Component quebra: "Functions cannot be passed
directly to Client Components").

Testado ponta a ponta com um tenant semeado (Acme Call Center): login →
/app direto, platform admin barrado de /app e vice-versa, dashboard com
numeros reais (zeros honestos), drawer mobile, dark mode.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EWHKmcVJtstQFErbZ1AanY

apps/frontend/src/components/shell/mobile-nav-drawer.tsx

@@ -0,0 +1,55 @@
+"use client";
+
+import { useState } from "react";
+import Image from "next/image";
+import * as Dialog from "@radix-ui/react-dialog";
+import { Menu, X } from "lucide-react";
+import { NavList } from "./nav-list";
+import type { NavSection } from "./nav-types";
+
+/** Drawer de navegação pra telas abaixo de `lg` (secao 175: notebook/
+ * tablet são prioridade, mas o próprio celular do agente precisa
+ * funcionar) — a sidebar fixa de 256px não cabe num viewport de celular.
+ * Radix Dialog dá foco preso + Escape + clique fora de graça (secao 176:
+ * navegação completa por teclado). */
+export function MobileNavDrawer({ items }: { items: NavSection[] }) {
+  const [open, setOpen] = useState(false);
+
+  return (
+    <Dialog.Root open={open} onOpenChange={setOpen}>
+      <Dialog.Trigger asChild>
+        <button
+          type="button"
+          aria-label="Abrir menu de navegação"
+          className="flex h-9 w-9 shrink-0 items-center justify-center rounded-md text-muted-foreground hover:bg-muted hover:text-foreground focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring lg:hidden"
+        >
+          <Menu className="h-5 w-5" aria-hidden />
+        </button>
+      </Dialog.Trigger>
+      <Dialog.Portal>
+        <Dialog.Overlay className="fixed inset-0 z-40 bg-[hsl(224_45%_11%)]/50 opacity-0 backdrop-blur-[1px] transition-opacity duration-200 data-[state=open]:opacity-100" />
+        <Dialog.Content
+          className="fixed inset-y-0 left-0 z-50 flex w-72 max-w-[85vw] -translate-x-full flex-col bg-surface shadow-pop outline-none transition-transform duration-200 ease-out data-[state=open]:translate-x-0"
+          aria-describedby={undefined}
+        >
+          <Dialog.Title className="sr-only">Navegação</Dialog.Title>
+          <div className="flex h-16 items-center justify-between border-b border-border px-4">
+            <Image src="/branding/b2blogo.png" alt="B2BCall" width={110} height={27} />
+            <Dialog.Close asChild>
+              <button
+                type="button"
+                aria-label="Fechar menu"
+                className="flex h-8 w-8 items-center justify-center rounded-md text-muted-foreground hover:bg-muted hover:text-foreground focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring"
+              >
+                <X className="h-4 w-4" aria-hidden />
+              </button>
+            </Dialog.Close>
+          </div>
+          <nav className="flex-1 overflow-y-auto px-2 py-3" aria-label="Navegação principal">
+            <NavList items={items} onNavigate={() => setOpen(false)} />
+          </nav>
+        </Dialog.Content>
+      </Dialog.Portal>
+    </Dialog.Root>
+  );
+}