feat: 新增引导式新手指引 (OnboardingTour) 组件，全站页面接入

src/features/character-mix/CharacterMixPage.tsx

@@ -61,6 +61,9 @@ function CharacterMixPage({
   const abortRef = useRef(false);
   const taskIdRef = useRef<string | null>(null);
   const [isDragging, setIsDragging] = useState(false);
+  const [isCanvasDragging, setIsCanvasDragging] = useState(false);
+  const characterInputRef = useRef<HTMLInputElement | null>(null);
+  const videoInputRef = useRef<HTMLInputElement | null>(null);
 
   useEffect(() => {
     return () => {
@@ -262,6 +265,23 @@ function CharacterMixPage({
     }
   };
 
+  const handleCanvasDragOver = (e: DragEvent) => { e.preventDefault(); e.stopPropagation(); if (e.dataTransfer.types.includes("Files")) setIsCanvasDragging(true); };
+  const handleCanvasDragLeave = (e: DragEvent) => { e.preventDefault(); e.stopPropagation(); if (e.currentTarget === e.target || !e.currentTarget.contains(e.relatedTarget as Node)) setIsCanvasDragging(false); };
+  const handleCanvasDrop = (e: DragEvent) => {
+    e.preventDefault();
+    e.stopPropagation();
+    setIsCanvasDragging(false);
+    handleDrop(e);
+  };
+
+  const handleCanvasClick = () => {
+    if (!characterPreview) {
+      characterInputRef.current?.click();
+    } else if (!videoPreview) {
+      videoInputRef.current?.click();
+    }
+  };
+
   return (
     <section className="image-workbench-page character-mix-page" aria-label="角色迁移">
       <header className="image-workbench-topbar">
@@ -342,6 +362,7 @@ function CharacterMixPage({
               <div className="studio-panel__section-body">
                 <label className={characterFile ? "studio-upload-slot--filled" : "studio-upload-slot--empty"}>
                   <input
+                    ref={characterInputRef}
                     type="file"
                     accept="image/*"
                     onChange={(event) => {
@@ -383,6 +404,7 @@ function CharacterMixPage({
               <div className="studio-panel__section-body">
                 <label className={videoFile ? "studio-upload-slot--filled" : "studio-upload-slot--empty"}>
                   <input
+                    ref={videoInputRef}
                     type="file"
                     accept="video/*"
                     onChange={(event) => {
@@ -441,12 +463,21 @@ function CharacterMixPage({
               ) : null}
             </div>
           ) : (
-            <div className="studio-canvas-ghost">
+            <div
+              className={`studio-canvas-ghost${isCanvasDragging ? " is-dragging" : ""}`}
+              onClick={handleCanvasClick}
+              onDragOver={handleCanvasDragOver}
+              onDragLeave={handleCanvasDragLeave}
+              onDrop={handleCanvasDrop}
+              role="button"
+              tabIndex={0}
+              onKeyDown={(e) => { if (e.key === "Enter" || e.key === " ") handleCanvasClick(); }}
+            >
               <div className="studio-canvas-ghost__icon">
                 <SwapOutlined />
               </div>
               <div className="studio-canvas-ghost__title">上传人物图与参考视频</div>
-              <div className="studio-canvas-ghost__hint">将静态角色迁移到参考视频的动作与表情中。</div>
+              <div className="studio-canvas-ghost__hint">点击或拖拽上传；支持人物图片 (PNG/JPG) 和参考视频 (MP4/MOV/AVI)</div>
             </div>
           )
         }