Add supports_float64() to OmniPlatform and clean up MPS (#2488)

Signed-off-by: Xiaodong Ye <yeahdongcn@gmail.com>

vllm_omni/platforms/interface.py

@@ -117,6 +117,10 @@ class OmniPlatform(Platform):
     def supports_cpu_offload(cls) -> bool:
         return True
 
+    @classmethod
+    def supports_float64(cls) -> bool:
+        return True
+
     @classmethod
     def set_device_control_env_var(cls, devices: str | int | None) -> None:
         import os