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/ko.ts

@@ -11,6 +11,10 @@ export const dict: Record<I18nKey, string> = {
   'chat.message.context.chatQuote': '이전 메시지에서 인용',
   'chat.chatInput.chatQuoteContext': '채팅 인용',
   'chat.chatInput.chatQuoteContextRemove': '채팅 인용 제거',
+  'chat.chatInput.contextPreview.selectedLabel': '선택한 텍스트',
+  'chat.chatInput.contextPreview.commentLabel': '사용자 댓글',
+  'chat.chatInput.contextPreview.edit': '댓글 편집',
+  'chat.chatInput.contextPreview.remove': '제거',
   'chat.message.context.browserAnnotation': '브라우저 주석 ({page})',
   'chat.message.context.prComment': 'GitHub PR 댓글 ({label})',
   'chat.message.context.prCheck': '실패한 GitHub PR 검사 ({label})',