feat: 新增 K26 图生视频节点

- 新增 nodes/K_video.py，节点显示名称「K26 图生视频」
- 支持起始帧（必填）、尾帧（可选）图片输入
- 参数：提示词、模式(pro)、时长(5/10s)、生成音频(关闭/打开)
- 模型名按规则动态拼接：kling-v2-6-{mode}-{dur}s-{voice}
- 尾帧有输入时通过 metadata.image_tail 传参
- 走三段式流程：提交 → 轮询 → 下载，带进度条
- 注册至 NODE_CLASS_MAPPINGS / NODE_DISPLAY_NAME_MAPPINGS

__init__.py

@@ -21,7 +21,7 @@ except Exception:
 
 import ssl
 
-from .nodes import NanoBananaPro, BatchNanoBananaPro, GoogleGemini, LoadFile, ImageStitchPro, SaveCleanImage, BatchCleanMetadata, VideoPreview, GoogleVeo, FluxImageEdit, UniversalLLMChat, KlingVideo, KlingFirstLastFrame, KlingMotionControlTest, AspectRatioPreset, MultiResPreview, BatchImagesO1key, Seedance, SeedanceMultiModal, StreamPreview, DoubaoImage, O1keyGPTImage
+from .nodes import NanoBananaPro, BatchNanoBananaPro, GoogleGemini, LoadFile, ImageStitchPro, SaveCleanImage, BatchCleanMetadata, VideoPreview, GoogleVeo, FluxImageEdit, UniversalLLMChat, KlingVideo, KlingFirstLastFrame, KlingMotionControlTest, AspectRatioPreset, MultiResPreview, BatchImagesO1key, Seedance, SeedanceMultiModal, StreamPreview, DoubaoImage, O1keyGPTImage, KVideo
 
 # 报错弹框友好文案（不修改原节点代码，仅在外层统一处理）
 _MSG_TIMEOUT = "API 请求超时，请稍后重试或检查网络。"
@@ -80,6 +80,7 @@ NODE_CLASS_MAPPINGS = {
     "StreamPreview": StreamPreview,
     "DoubaoImage": DoubaoImage,
     "O1keyGPTImage": O1keyGPTImage,
+    "KVideo": KVideo,
 }
 
 NODE_DISPLAY_NAME_MAPPINGS = {
@@ -105,6 +106,7 @@ NODE_DISPLAY_NAME_MAPPINGS = {
     "StreamPreview": "流式文本预览",
     "DoubaoImage": "豆包生图",
     "O1keyGPTImage": "o1key GPT Image",
+    "KVideo": "K26 图生视频",
 }
 
 WEB_DIRECTORY = "./web"