Add example/visualize scripts + requirements + usage docs

requirements.txt

@@ -0,0 +1,10 @@
+# ===== 运行示例脚本 example_usage.py =====
+# lerobot 需要 Python >= 3.10，会自动安装 torch
+lerobot>=0.4.3
+numpy
+Pillow
+
+# ===== 运行可视化脚本 visualize_dataset.py =====
+pyarrow
+opencv-python
+scipy