feat: 新增波形能量动画系统 plot_wave.py

- 创建 plot_wave.py: 从 display.txt 读取原子位移数据
  绘制纵波(x) + 横波(y) + 横波(z) 波形随时间的动画
  同时绘制系统动能/弹性势能/总能量/输入功率(dE/dt)时变曲线
  输出 wave_animation.gif
- 所有 input.txt 新增 step_plot_wave: 0 开关
- case05 开启 step_plot_wave: 1
- dynamics.py disp_data 新增 bond_stiffness/bond_rest_lengths
- 更新案例文档

examples/case06/run_dynamics.py

@@ -0,0 +1,54 @@
+"""
+Case runner for Dynamics case05 — 1D atomic chain.
+
+This script keeps program and data separated:
+  - program: ../../dynamics.py
+  - input:   ./input
+  - output:  ./output
+"""
+
+from __future__ import annotations
+
+import argparse
+import importlib.util
+from pathlib import Path
+
+
+CASE_DIR = Path(__file__).resolve().parent
+DYNAMICS_PATH = Path("..") / ".." / "dynamics.py"
+INPUT_DIR = Path("input")
+OUTPUT_DIR = Path("output")
+CONFIG_FILE = INPUT_DIR / "input.txt"
+
+
+def load_dynamics_module(module_path: Path):
+    spec = importlib.util.spec_from_file_location("dynamics_module", module_path)
+    if spec is None or spec.loader is None:
+        raise ImportError(f"无法加载 dynamics.py: {module_path}")
+    module = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(module)
+    return module
+
+
+def main():
+    parser = argparse.ArgumentParser(description="运行 Dynamics 示例案例 case01")
+    parser.add_argument("--no-plot", action="store_true", help="跳过 matplotlib 绘图")
+    args = parser.parse_args()
+
+    dynamics_path = (CASE_DIR / DYNAMICS_PATH).resolve()
+    input_dir = (CASE_DIR / INPUT_DIR).resolve()
+    output_dir = (CASE_DIR / OUTPUT_DIR).resolve()
+    config_path = (CASE_DIR / CONFIG_FILE).resolve()
+
+    module = load_dynamics_module(dynamics_path)
+    module.run_case(
+        config_path=config_path,
+        runtime_base=CASE_DIR,
+        input_dir=input_dir,
+        output_dir=output_dir,
+        no_plot=args.no_plot,
+    )
+
+
+if __name__ == "__main__":
+    main()