feat: move_camera.txt 改为速度段格式驱动相机运动

格式：
  1-60   vx=1.0  rx=10         # 1-60帧：x平移1/帧 + 绕x转10°/帧
  30-90  vy=2.0  ry=20  rz=10  # 30-90帧：y平移2/帧 + 绕y转20°/帧 + 绕z转10°/帧

draw.py 每帧累加平移速度修改center，累加旋转速度修改
elevation/azimuth，实现连续平滑的相机运动。

dynamics.py

@@ -33,7 +33,8 @@ def _fmt_alpha(v):
 
 
 def _load_camera_kf(config, runtime_base):
-    """加载 move_camera.txt → JSON 字符串，供 display.txt header 使用。"""
+    """加载 move_camera.txt（速度段格式）→ JSON 字符串。"""
+    import re, json
     if not int(config.get("move_camera", 0)):
         return ""
     cam_file = str(config.get("move_camera_file",
@@ -43,18 +44,25 @@ def _load_camera_kf(config, runtime_base):
         cam_path = os.path.join(runtime_base, cam_file)
     if not os.path.exists(cam_path):
         return ""
-    import json
-    kfs = []
+    segments = []
     with open(cam_path, "r", encoding="utf-8") as f:
         for line in f:
             line = line.strip()
             if not line or line.startswith("#"):
                 continue
-            parts = line.split()
-            if len(parts) >= 4:
-                kfs.append([int(parts[0]), float(parts[1]),
-                            float(parts[2]), float(parts[3])])
-    return json.dumps(kfs) if kfs else ""
+            m = re.match(r'(\d+)\s*-\s*(\d+)', line)
+            if not m:
+                continue
+            start, end = int(m.group(1)), int(m.group(2))
+            v, r = [0.0, 0.0, 0.0], [0.0, 0.0, 0.0]
+            for i, axis in enumerate(['x', 'y', 'z']):
+                m2 = re.search(r'v' + axis + r'\s*=\s*([-\d.]+)', line)
+                if m2: v[i] = float(m2.group(1))
+                m2 = re.search(r'r' + axis + r'\s*=\s*([-\d.]+)', line)
+                if m2: r[i] = float(m2.group(1))
+            if any(v) or any(r):
+                segments.append({"start": start, "end": end, "v": v, "r": r})
+    return json.dumps(segments) if segments else ""
 
 
 def read_optional_index(data, key, default_value):