[diffusion] feat: support parallel wan-vae decode (sgl-project#18179)

Author: nono-Sang

python/sglang/multimodal_gen/configs/models/vaes/wanvae.py

@@ -82,6 +82,9 @@ class WanVAEConfig(VAEConfig):
     use_temporal_tiling: bool = False
     use_parallel_tiling: bool = False
 
+    use_parallel_encode: bool = True
+    use_parallel_decode: bool = True
+
     def __post_init__(self):
         self.blend_num_frames = (
             self.tile_sample_min_num_frames - self.tile_sample_stride_num_frames