feat: Implement video generation functionality and integrate with Kling API.

models/enums.py

@@ -34,10 +34,12 @@ class Quality(str, Enum):
 class GenType(str, Enum):
     TEXT = 'Text'
     IMAGE = 'Image'
+    VIDEO = 'Video'
 
     @property
     def value_type(self) -> str:
         return {
             GenType.TEXT: 'Text',
             GenType.IMAGE: 'Image',
+            GenType.VIDEO: 'Video',
         }[self]