feat: add regenerate all previews functionality and update localization strings

qwen3-tts-frontend/src/locales/en-US/audiobook.json

@@ -85,7 +85,12 @@
       "voiceDesign": "Voice #{{id}}",
       "noVoice": "Unassigned",
       "editTitle": "Edit Character: {{name}}",
-      "savedSuccess": "Character saved"
+      "savedSuccess": "Character saved",
+      "regeneratingPreview": "Regenerating...",
+      "regeneratePreview": "Regenerate Preview",
+      "regenerateAll": "Regenerate All Previews",
+      "regenerateAllDone": "All previews regenerated",
+      "previewNotReady": "Collecting preview..."
     },
 
     "confirm": {

qwen3-tts-frontend/src/locales/ja-JP/audiobook.json

@@ -84,7 +84,12 @@
       "voiceDesign": "音声 #{{id}}",
       "noVoice": "未割り当て",
       "editTitle": "キャラクターを編集：{{name}}",
-      "savedSuccess": "キャラクターを保存しました"
+      "savedSuccess": "キャラクターを保存しました",
+      "regeneratingPreview": "試聴を再生成中...",
+      "regeneratePreview": "試聴を再生成",
+      "regenerateAll": "試聴を一括再生成",
+      "regenerateAllDone": "すべての試聴を再生成しました",
+      "previewNotReady": "試聴を収集中..."
     },
 
     "confirm": {

qwen3-tts-frontend/src/locales/ko-KR/audiobook.json

@@ -84,7 +84,12 @@
       "voiceDesign": "음성 #{{id}}",
       "noVoice": "미할당",
       "editTitle": "캐릭터 편집: {{name}}",
-      "savedSuccess": "캐릭터가 저장되었습니다"
+      "savedSuccess": "캐릭터가 저장되었습니다",
+      "regeneratingPreview": "미리듣기 재생성 중...",
+      "regeneratePreview": "미리듣기 재생성",
+      "regenerateAll": "미리듣기 일괄 재생성",
+      "regenerateAllDone": "모든 미리듣기가 재생성되었습니다",
+      "previewNotReady": "미리듣기 수집 중..."
     },
 
     "confirm": {

qwen3-tts-frontend/src/locales/zh-CN/audiobook.json

@@ -88,6 +88,8 @@
       "savedSuccess": "角色已保存",
       "regeneratingPreview": "重新生成试听中...",
       "regeneratePreview": "重生试听",
+      "regenerateAll": "一键重新生成试听",
+      "regenerateAllDone": "所有试听已重新生成",
       "previewNotReady": "试听收集中..."
     },
 

qwen3-tts-frontend/src/locales/zh-TW/audiobook.json

@@ -84,7 +84,12 @@
       "voiceDesign": "音色 #{{id}}",
       "noVoice": "未分配",
       "editTitle": "編輯角色：{{name}}",
-      "savedSuccess": "角色已儲存"
+      "savedSuccess": "角色已儲存",
+      "regeneratingPreview": "重新生成試聽中...",
+      "regeneratePreview": "重生試聽",
+      "regenerateAll": "一鍵重新生成試聽",
+      "regenerateAllDone": "所有試聽已重新生成",
+      "previewNotReady": "試聽收集中..."
     },
 
     "confirm": {

qwen3-tts-frontend/src/pages/Audiobook.tsx

@@ -1190,6 +1190,24 @@ function CharactersPanel({
     }
   }
 
+  const handleRegenerateAllPreviews = async () => {
+    const charsWithVoice = detail?.characters.filter(c => c.voice_design_id) ?? []
+    if (charsWithVoice.length === 0) return
+    const ids = charsWithVoice.map(c => c.id)
+    setRegeneratingVoices(new Set(ids))
+    for (const id of ids) {
+      try {
+        await audiobookApi.regenerateCharacterPreview(project.id, id)
+        setVoiceKeys(prev => ({ ...prev, [id]: (prev[id] || 0) + 1 }))
+      } catch (e: any) {
+        toast.error(`${detail?.characters.find(c => c.id === id)?.name}: ${formatApiError(e)}`)
+      } finally {
+        setRegeneratingVoices(prev => { const n = new Set(prev); n.delete(id); return n })
+      }
+    }
+    toast.success(t('projectCard.characters.regenerateAllDone'))
+  }
+
 
   const charCount = detail?.characters.length ?? 0
   const hasChaptersOutline = (detail?.chapters.length ?? 0) > 0
@@ -1237,6 +1255,20 @@ function CharactersPanel({
             {t('projectCard.reanalyze')}
           </Button>
         )}
+        {!isActive && status === 'characters_ready' && (detail?.characters.some(c => c.voice_design_id) ?? false) && (
+          <Button
+            size="xs"
+            variant="ghost"
+            className="text-muted-foreground"
+            onClick={handleRegenerateAllPreviews}
+            disabled={regeneratingVoices.size > 0}
+          >
+            {regeneratingVoices.size > 0
+              ? <><Loader2 className="h-3 w-3 mr-1 animate-spin" />{t('projectCard.characters.regeneratingPreview')}</>
+              : <><RefreshCw className="h-3 w-3 mr-1" />{t('projectCard.characters.regenerateAll')}</>
+            }
+          </Button>
+        )}
         {hasChaptersOutline && (
           <Button size="icon" variant="ghost" className="h-6 w-6" onClick={onToggle}>
             <PanelLeftClose className="h-3.5 w-3.5" />