refactor(actpred): 模型输入尺寸 image_size → image_width/image_height，默认 1920×1080

config/model/dataset/train/pretrain/predict/export 全链路适配非方形输入，
hailo_infer/onnx_infer 从模型元数据动态推导宽高；旧 224 checkpoint 配置键
不兼容（重训后替换）。Pi 5 CPU 冒烟验证 1080p 训练可行（~4.75s/步 batch=2）。

actpred/export_onnx.py

@@ -21,7 +21,7 @@ def main():
     model.eval()
 
     dummy_images = torch.randn(
-        1, data_cfg.frame_len, 3, data_cfg.image_size, data_cfg.image_size)
+        1, data_cfg.frame_len, 3, data_cfg.image_height, data_cfg.image_width)
     dummy_history = torch.randn(1, data_cfg.history_len, data_cfg.action_dim)
 
     batch = Dim("batch")