feat(composer): context chip previews with inline comment editing

Hovering (or tapping) a context chip opens a stacked preview of its
pending items above the composer: numbered entries with a muted header
band, the captured selection, and the user's comment, which can be
edited in place (save/cancel) or removed before sending. The chips
component now subscribes to the draft store itself; the per-kind count
plumbing in ChatInput is gone.

packages/ui/src/lib/i18n/messages/pt-BR.ts

@@ -11,6 +11,10 @@ export const dict: Record<I18nKey, string> = {
   'chat.message.context.chatQuote': 'Citação de uma mensagem anterior',
   'chat.chatInput.chatQuoteContext': 'Citações do chat',
   'chat.chatInput.chatQuoteContextRemove': 'Remover citações do chat',
+  'chat.chatInput.contextPreview.selectedLabel': 'Texto selecionado',
+  'chat.chatInput.contextPreview.commentLabel': 'Comentário do usuário',
+  'chat.chatInput.contextPreview.edit': 'Editar comentário',
+  'chat.chatInput.contextPreview.remove': 'Remover',
   'chat.message.context.browserAnnotation': 'Anotação do navegador ({page})',
   'chat.message.context.prComment': 'Comentário de PR do GitHub ({label})',
   'chat.message.context.prCheck': 'Verificação de PR do GitHub com falha ({label})',