fix(frontend): #1898 配音库AI配音增加情绪语言选择

- TTS 弹窗新增情绪下拉（自然/兴奋/沉稳/亲切，默认自然）和语言下拉（中文/英文/日文/韩文，默认中文）
- 新增 EmotionControl、LanguageControl 组件，与 SpeedControl 风格一致（tts-modal 目录下）
- useTtsSynthesize hook 管理 emotion/language 状态，关闭弹窗时重置
- synthesizeSpeech 请求真实传递 emotion 和 language 参数到后端
- VoiceModals/VoiceLibrary 全链路透传新增 props
- api/tts/types 的 TTSSynthesizeRequest 和 TTSPreviewRequest 补充 emotion/language 类型

apps/web/src/pages/voices/components/tts-modal/LanguageControl.tsx

@@ -0,0 +1,47 @@
+import React from "react"
+import { TTS_LANGUAGE_OPTIONS, type TtsLanguage } from "./constants"
+
+interface LanguageControlProps {
+  language: TtsLanguage
+  onChange: (language: TtsLanguage) => void
+}
+
+/** 语言选择下拉 */
+const LanguageControl: React.FC<LanguageControlProps> = ({ language, onChange }) => {
+  return (
+    <div>
+      <div
+        style={{
+          fontSize: 13,
+          color: "var(--text-secondary)",
+          marginBottom: 6,
+        }}
+      >
+        语言
+      </div>
+      <select
+        value={language}
+        onChange={(e) => onChange(e.target.value as TtsLanguage)}
+        style={{
+          width: "100%",
+          padding: "7px 10px",
+          borderRadius: 6,
+          border: "1px solid var(--border-color, #e5e7eb)",
+          background: "var(--bg-primary, #fff)",
+          color: "var(--text-primary)",
+          fontSize: 13,
+          outline: "none",
+          cursor: "pointer",
+        }}
+      >
+        {TTS_LANGUAGE_OPTIONS.map((opt) => (
+          <option key={opt.value} value={opt.value}>
+            {opt.label}
+          </option>
+        ))}
+      </select>
+    </div>
+  )
+}
+
+export default LanguageControl