refactor: 统一采样路径为 Strategy + batch tensor，删除 apply_sampling_strategies

- TemperatureStrategy / TopKStrategy / TopPStrategy 支持 Union[float, Tensor]
- SamplingPipeline.sample() 一条调用完成 apply + softmax + multinomial
- 新增 sample() 独立函数作为 scheduler 入口
- scheduler decode 改为 batch tensor 参数传递，支持任意 batch size
- 删除 apply_sampling_strategies（被 sample() 取代）

astrai/inference/__init__.py

@@ -19,7 +19,7 @@ from astrai.inference.sampling import (
     TemperatureStrategy,
     TopKStrategy,
     TopPStrategy,
-    apply_sampling_strategies,
+    sample,
 )
 from astrai.inference.scheduler import (
     InferenceScheduler,
@@ -37,7 +37,7 @@ __all__ = [
     "Task",
     "TaskStatus",
     # Sampling (Strategy pattern)
-    "apply_sampling_strategies",
+    "sample",
     "BaseSamplingStrategy",
     "TemperatureStrategy",
     "TopKStrategy",