feat: 多页面拖拽上传、滚动条精简、UI优化

- 剧本评测/分辨率提升/数字人/角色迁移/图片工作台/去水印/电商：新增外部拖拽文件上传
- 电商：爆款图复刻上传框支持拖拽+大滚动条，短视频/模特图/详情图滚动条精简回退
- 图片工作台：右侧输出面板移至左侧提示词上方，删除局部重绘遮罩/结果框
- 数字人：生成按钮改为「开始生成」
- 局部重绘：编辑遮罩→编辑页面
- 对话框生成器：新增对话/视频模式、模型/速度/深度选择按钮
- 视频时长默认改为5秒
- 工具箱页面空状态logo统一绿底亮色图标
- 多处CSS滚动条和布局优化

src/features/workbench/WorkbenchPage.tsx

@@ -99,6 +99,9 @@ import {
   type WorkbenchKeepaliveTask,
   MODE_META,
   MODE_OPTIONS,
+  CHAT_MODEL_OPTIONS,
+  THINKING_SPEED_OPTIONS,
+  THINKING_DEPTH_OPTIONS,
   IMAGE_MODEL_OPTIONS,
   VIDEO_MODEL_OPTIONS,
   RATIO_OPTIONS,
@@ -330,9 +333,13 @@ function WorkbenchPage({
   const [videoModel, setVideoModel] = useState(VIDEO_MODEL_OPTIONS[0].value);
   const [videoFrameMode, setVideoFrameMode] = useState("omni");
   const [videoRatio, setVideoRatio] = useState("16:9");
-  const [videoDuration, setVideoDuration] = useState("4");
+  const [videoDuration, setVideoDuration] = useState("5");
   const [videoQuality, setVideoQuality] = useState(() => getDefaultVideoQuality(VIDEO_MODEL_OPTIONS[0].value));
 
+  const [chatModel, setChatModel] = useState(CHAT_MODEL_OPTIONS[0].value);
+  const [thinkingSpeed, setThinkingSpeed] = useState(THINKING_SPEED_OPTIONS[0].value);
+  const [thinkingDepth, setThinkingDepth] = useState(THINKING_DEPTH_OPTIONS[0].value);
+
   useEffect(() => {
     let cancelled = false;
 
@@ -388,13 +395,13 @@ function WorkbenchPage({
   const referenceCount = referenceItems.length;
   const activeVideoModelValue = toHappyHorseDisplayModel(videoModel);
   const activeModelValue =
-    activeMode === "image" ? imageModel : activeMode === "video" ? activeVideoModelValue : CHAT_MODEL;
+    activeMode === "image" ? imageModel : activeMode === "video" ? activeVideoModelValue : chatModel;
   const activeModel =
     activeMode === "image"
       ? imageModelOptions.find((item) => item.value === imageModel)?.label || imageModel
       : activeMode === "video"
         ? videoModelOptions.find((item) => item.value === activeVideoModelValue)?.label || activeVideoModelValue
-        : "OmniChat";
+        : CHAT_MODEL_OPTIONS.find((item) => item.value === chatModel)?.label || chatModel;
   const conversationRecords = useMemo<WebProjectSummary[]>(
     () =>
       conversations.map((conversation) => ({
@@ -2648,6 +2655,46 @@ function WorkbenchPage({
           ariaLabel="工作台模式"
           direction={dropdownDirection}
         />
+        {activeMode === "chat" && (
+          <>
+            <SelectChip
+              chipId="chat-model"
+              value={chatModel}
+              options={CHAT_MODEL_OPTIONS}
+              disabled={disabled}
+              isOpen={toolbarMenuId === "chat-model"}
+              onToggle={() => toggleToolbarMenu("chat-model")}
+              onClose={closeToolbarMenus}
+              onChange={setChatModel}
+              ariaLabel="对话模型"
+              direction={dropdownDirection}
+            />
+            <SelectChip
+              chipId="chat-speed"
+              value={thinkingSpeed}
+              options={THINKING_SPEED_OPTIONS}
+              disabled={disabled}
+              isOpen={toolbarMenuId === "chat-speed"}
+              onToggle={() => toggleToolbarMenu("chat-speed")}
+              onClose={closeToolbarMenus}
+              onChange={setThinkingSpeed}
+              ariaLabel="思考速度"
+              direction={dropdownDirection}
+            />
+            <SelectChip
+              chipId="chat-depth"
+              value={thinkingDepth}
+              options={THINKING_DEPTH_OPTIONS}
+              disabled={disabled}
+              isOpen={toolbarMenuId === "chat-depth"}
+              onToggle={() => toggleToolbarMenu("chat-depth")}
+              onClose={closeToolbarMenus}
+              onChange={setThinkingDepth}
+              ariaLabel="思考深度"
+              direction={dropdownDirection}
+            />
+          </>
+        )}
         {activeMode === "image" && (
           <>
             <SelectChip