fix: mobile diff comment input placeholder and review comments pill

Use a shorter comment placeholder on mobile (drop the Cmd+Enter hint that has
no touch equivalent) so it no longer clips in the auto-sized textarea.

Add a remove (x) button to the review comments pill, matching the annotation
and dev-server-log pills, and stop the mobile touch-target min-height/width
from inflating the pill close buttons.

packages/ui/src/lib/i18n/messages/zh-TW.ts

@@ -1216,6 +1216,7 @@ export const dict: Record<I18nKey, string> = {
   'rightSidebar.contextNotesTodo.toast.readPlanFileFailed': '讀取計畫檔案失敗',
   'inlineComment.range.lines': '行 {start}-{end}',
   'inlineComment.input.placeholder': '新增留言...（Cmd+Enter 儲存）',
+  'inlineComment.input.placeholderShort': '新增留言…',
   'inlineComment.actions.cancel': '取消',
   'inlineComment.actions.save': '儲存',
   'inlineComment.actions.comment': '留言',
@@ -1746,6 +1747,7 @@ export const dict: Record<I18nKey, string> = {
   'chat.chatInput.toast.openSessionFirst': '請先開啟一個會話',
   'chat.chatInput.toast.togglePermissionAutoAcceptFailed': '切換權限自動接受失敗',
   'chat.chatInput.reviewComments': '審查留言：',
+  'chat.chatInput.reviewCommentsRemove': '移除審查留言',
   'chat.chatInput.devServerLogs': 'Dev Server 日誌：',
   'chat.chatInput.devServerLogsRemove': '移除 Dev Server 日誌',
   'chat.chatInput.previewAnnotations': '預覽註釋：',