feat: polish scenarios and stabilize keyboard layout height

Add preset-driven polish scenarios (Settings, onboarding, ScenarioChip)
with ScenarioPrompt and style directives; drive keyboard height from
content (240pt) and use viewIsAppearing encapsulated-height offset for
smoother keyboard switches; remove redundant StatusBadge and hide system
dictation via hasDictationKey.

OSGKeyboardExt/zh-Hans.lproj/Keyboard.strings

@@ -76,7 +76,7 @@
 "settings.engine.local.legacy" = "端侧 ASR,仅转录,无润色。";
 "settings.engine.cloud.title" = "云端识别与润色";
 "settings.engine.cloud.subtitle" = "ASR 转录 + LLM 润色,需要 API Key。";
-"settings.provider.title" = "提供商";
+"settings.provider.title" = "云端引擎";
 "settings.provider.subtitle" = "选择 LLM 提供商。";
 "settings.api.title" = "接口";
 "settings.language.title" = "语言";
@@ -176,12 +176,16 @@
 "locale.chip.ja-JP" = "日";
 "locale.chip.ko-KR" = "韩";
 
-/* 翻译 chip (v0.2.1) */
-"keyboard.translation.off" = "翻译";
+/* Translation chip (v0.3) */
+"keyboard.translation.chip" = "翻译";
+"keyboard.translation.offMenu" = "不翻译";
+"keyboard.translation.off" = "不翻译";
 "keyboard.translation.enable" = "开启翻译";
 "keyboard.translation.disable" = "关闭翻译";
 "keyboard.translation.a11y" = "翻译";
 "keyboard.translation.a11yHint" = "切换翻译开关或修改目标语言。";
+"keyboard.scenario.a11y" = "润色场景";
+"keyboard.scenario.a11yHint" = "选择润色风格或使用场景。";
 
 /* Mode chip labels */
 "mode.off" = "关闭";