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

models/Generation.py

@@ -16,6 +16,7 @@ class GenerationStatus(str, Enum):
 class Generation(BaseModel):
     id: Optional[str] = None
     status: GenerationStatus = GenerationStatus.RUNNING
+    gen_type: GenType = GenType.IMAGE
     failed_reason: Optional[str] = None
     linked_character_id: Optional[str] = None
     telegram_id: Optional[int] = None
@@ -37,6 +38,10 @@ class Generation(BaseModel):
     album_id: Optional[str] = None  
     created_by: Optional[str] = None  # Stores User ID (Telegram ID or Web User ObjectId)
     project_id: Optional[str] = None
+    # Video-specific fields
+    kling_task_id: Optional[str] = None
+    video_duration: Optional[int] = None  # 5 or 10 seconds
+    video_mode: Optional[str] = None  # "std" or "pro"
     created_at: datetime = Field(default_factory=lambda: datetime.now(UTC))
     updated_at: datetime = Field(default_factory=lambda: datetime.now(UTC))