Fix XR teleop: body-frame IK control for mobile chassis

Switch arm IK from world-frame to body-frame control so that
pushing the XR controller forward always moves the arm in the
robot's forward direction, regardless of chassis rotation.

Key changes:
- dual_arm_agent: convert EEF observations to body frame before
  passing to XR controller; send body-frame IK targets directly
  (removed convert_action_world_to_root)
- xr_controller: XR deltas treated as body-frame deltas (no yaw
  rotation needed — VR view tracks robot heading naturally)
- streaming: add debug frame save for stereo alignment diagnostics
- mindrobot_2i_cfg: IdealPDActuator for trunk, disabled gravity
- Author headers updated to Yutang Li, SIAT

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

scripts/environments/teleoperation/teleop_xr_agent.py

@@ -43,7 +43,7 @@ parser.add_argument("--drive_turn", type=float, default=1.5)
 parser.add_argument("--stream-to", type=str, default=None, dest="stream_to")
 parser.add_argument("--stream-port", type=int, default=12345, dest="stream_port")
 parser.add_argument("--stream-bitrate", type=int, default=20_000_000, dest="stream_bitrate")
-parser.add_argument("--debug-viewports", action="store_true", dest="debug_viewports", default=False)
+parser.add_argument("--debug-viewports", action="store_true", dest="debug_viewports", default=True)
 
 AppLauncher.add_app_launcher_args(parser)
 args_cli = parser.parse_args()
@@ -95,7 +95,7 @@ def main() -> None:
             drive_speed=args.drive_speed, drive_turn=args.drive_turn,
             stream_to=args.stream_to, stream_port=args.stream_port,
             stream_bitrate=args.stream_bitrate,
-            debug_viewports=args.debug_viewports,
+            debug_viewports=args.debug_viewports or bool(args.stream_to),
         )
     elif is_dual_arm:
         print(f"[INFO] DualArmXrAgent (20D) | pos_sens={pos_sens} rot_sens={rot_sens}")