feat(home): add AI story expand button and modal

messages/zh/progress.json

@@ -65,6 +65,7 @@
     "screenplayConvert": "剧本转换",
     "voiceAnalyze": "台词分析",
     "analyzeGlobal": "全局分析",
+    "aiStoryExpand": "AI 故事扩写",
     "aiModifyAppearance": "角色描述修改",
     "aiModifyLocation": "场景描述修改",
     "aiModifyShotPrompt": "镜头提示词修改",
@@ -104,6 +105,8 @@
     "scriptToStoryboardStep": "执行分镜生成步骤",
     "scriptToStoryboardPersist": "保存分镜结果",
     "scriptToStoryboardPersistDone": "分镜与台词结果已保存",
+    "aiStoryExpandPrepare": "准备故事扩写参数",
+    "aiStoryExpandDone": "故事扩写已完成",
     "insertPanelGenerateText": "生成插入镜头文本",
     "insertPanelPersist": "保存插入镜头",
     "pollingExternal": "等待外部服务返回",