feat(i18n): translate the five systems users actually see

Ordered by what the group hits, not by string count.

  - Chat system messages ("X added Y to the group") and their sidebar
    preview twin. These are content, not chrome, so they sat in English in
    the middle of conversations.
  - Login, register and the invite landing page — the first screen anyone
    invited to the instance sees.
  - Voice — controls, connection info, the mobile join sheet, settings tab.
  - Mobile screens.
  - Settings navigation across space, user and instance, plus Discovery and
    join requests.

Three call sites build strings outside a component and so read the locale
directly rather than through the hook: the sidebar preview formatter, the
connection-info track labels, and MobileShell's screen map — which holds
plain functions that are *called*, not rendered, where a hook would run
under whichever component invoked the map. Each says so at the definition;
all three re-render often enough that a language switch shows through
promptly.

Adds a test for a mistake made three times in this series: a file with an
exported component plus a private sub-component, where only the exported one
got the hook. tsc catches it, but only after a full build and without naming
the component. The test names it, and also flags the inverse — a hook placed
below an early return, which tsc accepts and React breaks at runtime (this
project shipped that once, as error #310). Verified by mutation: removing a
hook makes it fail and print the component.

Dictionary is at 856 keys, en and pt-BR at exact parity.

Verified: web build (tsc + vite), 492 web tests.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/roadmap-resenha.md

@@ -110,6 +110,12 @@ fixas por `t('chave')`. O que faltar cai para o inglês sozinho.
 - Configurações do servidor → Cargos (incluindo a tabela de permissões)
 - Configurações da categoria (renomear, privacidade, exceções, excluir)
 - Configurações da instância → Geral (nome, descoberta, busca de GIFs)
+- Mensagens de sistema do chat e a prévia delas na barra lateral
+- Login, registro e a página de convite
+- Voz: controles, informações de conexão, folha de entrada no celular, aba Voz
+- Telas do celular (`Mobile*.tsx`)
+- Navegação das configurações (servidor, usuário e instância) + Descoberta e
+  pedidos de entrada
 
 Os rótulos de permissão viraram um conjunto único (`perm.*`), usado pelo painel
 de cargos e pelos editores de exceção de canal e de categoria — antes havia
@@ -118,8 +124,9 @@ duas cópias da mesma lista.
 ### Fila sugerida de tradução
 
 Configurações → Instância: registro, federação, transmissão, armazenamento e
-usuários · chrome do `SpaceSettings` e do `UserSettings` (abas) ·
-`ConnectedInstances` · `UserProfileModal` · telas móveis (`Mobile*.tsx`)
+usuários (os cinco painéis grandes, só o dono vê) · `ConnectedInstances` ·
+`UserProfileModal` · `MainContent` e `ChannelSidebar` · mensagens de erro
+vindas de stores e hooks (`instanceStore`, `useLiveKit`, `transferStore`)
 
 ## Correções pendentes