i18n: translate the chat composer and messages

Catching up on the fork's rule that every update also translates one existing
system — three updates went by without one.

The composer's placeholder takes the channel as a parameter rather than being
concatenated, since Portuguese puts the channel elsewhere in the sentence than
English does.

The translation hook is bound to `tr` in these two files, not `t`: both already
use `t` for transfer records in inner scopes, which shadowed the function and
made it uncallable exactly where it was needed.

packages/web/src/i18n/locales/pt-BR.ts

@@ -55,6 +55,25 @@ export const ptBR: Partial<Dictionary> = {
   'accountMenu.copyId': 'Copiar ID do usuário',
   'accountMenu.copied': 'Copiado',
 
+  // Chat — composer e mensagens
+  'chat.composer.placeholder': 'Conversar em {channel}',
+  'chat.composer.attach': 'Anexar arquivo',
+  'chat.composer.emoji': 'Emoji',
+  'chat.composer.gif': 'GIF',
+  'chat.composer.gifPicker': 'Seletor de GIF',
+  'chat.composer.emojiPicker': 'Seletor de emoji',
+  'chat.composer.send': 'Enviar',
+  'chat.composer.sendMessage': 'Enviar mensagem',
+  'chat.composer.uploading': 'Enviando',
+  'chat.composer.uploadingEllipsis': 'Enviando…',
+  'chat.composer.removeAttachment': 'Remover anexo',
+  'chat.composer.failedAttachment': 'Remova ou tente de novo o anexo que falhou para poder enviar',
+  'chat.composer.replyingTo': 'Respondendo a',
+  'chat.composer.cancelReply': 'Cancelar resposta',
+  'chat.message.addReaction': 'Adicionar reação',
+  'chat.message.edit': 'Editar',
+  'chat.message.reply': 'Responder',
+
   // Estatísticas
   'stats.title': 'Estatísticas',
   'stats.range.7': 'Últimos 7 dias',