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/xr_teleop/streaming.py

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: Copyright (c) 2022-2025, The Isaac Lab Project Developers.
+# Copyright (c) 2025, Yutang Li, SIAT (yt.li2@siat.ac.cn)
 # SPDX-License-Identifier: BSD-3-Clause
 
 """Sim-to-VR H264 stereo streaming manager."""
@@ -46,6 +46,8 @@ class StreamingManager:
     def enabled(self) -> bool:
         return self._enabled
 
+    _debug_saved = False
+
     def send(self, scene, frame_count: int = 0) -> None:
         """Send one stereo frame from scene cameras. Auto-disables on failure."""
         if not self._enabled:
@@ -53,6 +55,21 @@ class StreamingManager:
         try:
             left_rgb = scene["vr_left_eye"].data.output["rgb"][0].cpu().numpy()
             right_rgb = scene["vr_right_eye"].data.output["rgb"][0].cpu().numpy()
+
+            # Save debug images once (frame 5 to ensure rendering is stable)
+            if frame_count == 150 and not self._debug_saved:
+                self._debug_saved = True
+                try:
+                    from PIL import Image
+                    import numpy as np
+                    Image.fromarray(left_rgb[..., :3]).save("/tmp/vr_left_debug.png")
+                    Image.fromarray(right_rgb[..., :3]).save("/tmp/vr_right_debug.png")
+                    sbs = np.concatenate([left_rgb, right_rgb], axis=1)
+                    Image.fromarray(sbs[..., :3]).save("/tmp/vr_sbs_debug.png")
+                    print(f"[STREAM DIAG] Saved debug frames: left={left_rgb.shape}, right={right_rgb.shape}")
+                except Exception as e:
+                    print(f"[STREAM DIAG] Save failed: {e}")
+
             if not self._streamer.send_frame(left_rgb, right_rgb):
                 logger.warning("[Stream] Connection lost. Disabling streaming.")
                 self._enabled = False