feat(keyboard): harden polish/clipboard guards and ship 1.6.6 (build 59)

Keep marketing version at 1.6.6 and bump build to 59. Strengthen never-answer
polish safeguards, clipboard reply-intent continuity, voice undo UX, device
UITests harness, eval fixtures, and What's New assets.

OSGKeyboardExt/zh-Hans.lproj/Keyboard.strings

@@ -130,7 +130,7 @@
 "keyboard.clipboard.reject.secureField" = "密码框中不能使用剪贴板指令";
 "keyboard.clipboard.reject.noFullAccess" = "需要开启完全访问才能处理剪贴板";
 "keyboard.clipboard.reject.prepareFailed" = "麦克风未能及时就绪，请再试一次";
-"keyboard.clipboard.hint.hostStarting" = "正在启动，返回后请再长按处理剪贴板";
+"keyboard.clipboard.hint.hostStarting" = "正在启动，准备好后将自动录音；点按可取消";
 "keyboard.placeholder.processing" = "处理中…";
 "keyboard.placeholder.error" = "润色失败";
 "keyboard.placeholder.localBadge" = "本地";
@@ -144,6 +144,7 @@
 "keyboard.openSettingsA11y" = "打开 OSGKeyboard 设置";
 "keyboard.deniedHint" = "打开 OSGKeyboard 设置,可授予麦克风 / 语音识别权限。";
 "keyboard.tapToTalkA11y" = "点按说话";
+"keyboard.undoA11y" = "撤销上次听写";
 "keyboard.cursorDrag.hint" = "按住并拖动以移动光标";
 "keyboard.cursorDrag.centerHint" = "拖动移动光标";