Add Unitree Go2 robot + spatial-memory navigation base

unitree_go2 robot: high-level sport-mode body-velocity control over DDS
(unitree_sdk2py) straight from the host — no companion computer, unlike
the G1's low-level ZMQ bridge. Actions x.vel/y.vel/theta.vel; observation
is planar odometry (rt/sportmodestate) + the built-in front camera via
VideoClient. SDK imported only in connect() so configs/features/tests
work without it; 20 tests via mocks. unitree_go2 pyproject extra.

lerobot.navigation package: BaseController protocol + StubBaseController +
SafeBaseController (velocity clamp, occupancy gate, keyframe watchdog,
e-stop latch) + RobotBaseController wrapping any Robot on the standard
REP-103 mobile-base contract, carrying the world<->body velocity and
odometry<->world pose frame math. Robot-agnostic: the SDK lives only in
the robot class. 29 tests, SDK/torch-free.

First step of consolidating the dyna360 DynaMem navigation stack into
lerobot; dyna360 is a source to copy from, not a runtime dependency.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/robots/test_unitree_go2.py

@@ -0,0 +1,202 @@
+#!/usr/bin/env python
+
+# Copyright 2026 The HuggingFace Inc. team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Tests for the Unitree Go2 robot.
+
+The SDK is only imported inside ``UnitreeGo2.connect()``, so everything
+here runs without unitree_sdk2py installed: the sport client, state
+subscriber and video client are replaced with mocks.
+"""
+
+from types import SimpleNamespace
+from unittest.mock import MagicMock
+
+import cv2
+import numpy as np
+import pytest
+
+from lerobot.robots.unitree_go2 import UnitreeGo2, UnitreeGo2Config
+
+# ---------------------------------------------------------------------------
+# Config (no SDK needed)
+# ---------------------------------------------------------------------------
+
+
+class TestUnitreeGo2Config:
+    def test_registered_type_name(self):
+        assert UnitreeGo2Config().type == "unitree_go2"
+
+    def test_default_config(self):
+        cfg = UnitreeGo2Config()
+        assert cfg.domain_id == 0
+        assert cfg.use_front_camera is True
+        assert cfg.stand_on_connect is True
+        assert cfg.cameras == {}
+
+    def test_safety_clamps_are_positive(self):
+        cfg = UnitreeGo2Config()
+        assert cfg.max_x_vel > 0
+        assert cfg.max_y_vel > 0
+        assert cfg.max_theta_vel > 0
+
+
+# ---------------------------------------------------------------------------
+# Features (no SDK needed)
+# ---------------------------------------------------------------------------
+
+
+def _make_robot(**cfg_kwargs) -> UnitreeGo2:
+    cfg = UnitreeGo2Config(id="test_go2", **cfg_kwargs)
+    return UnitreeGo2(cfg)
+
+
+class TestFeatures:
+    def test_action_features(self):
+        robot = _make_robot()
+        assert robot.action_features == {"x.vel": float, "y.vel": float, "theta.vel": float}
+
+    def test_observation_features_with_front_camera(self):
+        robot = _make_robot()
+        ft = robot.observation_features
+        assert ft["front"] == (720, 1280, 3)
+        for key in ("x.pos", "y.pos", "theta.pos", "x.vel", "y.vel", "theta.vel"):
+            assert ft[key] is float
+
+    def test_observation_features_without_front_camera(self):
+        robot = _make_robot(use_front_camera=False)
+        assert "front" not in robot.observation_features
+
+    def test_features_available_before_connect(self):
+        robot = _make_robot()
+        assert not robot.is_connected
+        assert robot.observation_features
+        assert robot.action_features
+
+    def test_is_calibrated_always_true(self):
+        assert _make_robot().is_calibrated is True
+
+
+# ---------------------------------------------------------------------------
+# I/O with mocked SDK handles
+# ---------------------------------------------------------------------------
+
+
+def _connected_robot(**cfg_kwargs) -> UnitreeGo2:
+    """A robot with mocked SDK handles, as if connect() had run."""
+    robot = _make_robot(**cfg_kwargs)
+    robot._sport = MagicMock()
+    robot._video = MagicMock()
+    robot._connected = True
+    return robot
+
+
+def _fake_state(x=0.0, y=0.0, yaw=0.0, vx=0.0, vy=0.0, yaw_speed=0.0):
+    return SimpleNamespace(
+        position=[x, y, 0.0],
+        velocity=[vx, vy, 0.0],
+        yaw_speed=yaw_speed,
+        imu_state=SimpleNamespace(rpy=[0.0, 0.0, yaw]),
+    )
+
+
+class TestSendAction:
+    def test_action_reaches_sport_move(self):
+        robot = _connected_robot()
+        sent = robot.send_action({"x.vel": 0.3, "y.vel": -0.1, "theta.vel": 0.5})
+        robot._sport.Move.assert_called_once_with(0.3, -0.1, 0.5)
+        assert sent == {"x.vel": 0.3, "y.vel": -0.1, "theta.vel": 0.5}
+
+    def test_action_is_clamped(self):
+        robot = _connected_robot(max_x_vel=0.5, max_y_vel=0.2, max_theta_vel=1.0)
+        sent = robot.send_action({"x.vel": 9.0, "y.vel": -9.0, "theta.vel": -9.0})
+        robot._sport.Move.assert_called_once_with(0.5, -0.2, -1.0)
+        assert sent == {"x.vel": 0.5, "y.vel": -0.2, "theta.vel": -1.0}
+
+    def test_missing_keys_default_to_zero(self):
+        robot = _connected_robot()
+        sent = robot.send_action({})
+        robot._sport.Move.assert_called_once_with(0.0, 0.0, 0.0)
+        assert sent == {"x.vel": 0.0, "y.vel": 0.0, "theta.vel": 0.0}
+
+    def test_raises_when_not_connected(self):
+        robot = _make_robot()
+        with pytest.raises(ConnectionError):
+            robot.send_action({"x.vel": 0.1})
+
+
+class TestGetObservation:
+    def test_odometry_fields(self):
+        robot = _connected_robot(use_front_camera=False)
+        robot._latest_state = _fake_state(x=1.0, y=2.0, yaw=0.3, vx=0.1, vy=-0.05, yaw_speed=0.2)
+        obs = robot.get_observation()
+        assert obs["x.pos"] == pytest.approx(1.0)
+        assert obs["y.pos"] == pytest.approx(2.0)
+        assert obs["theta.pos"] == pytest.approx(0.3)
+        assert obs["x.vel"] == pytest.approx(0.1)
+        assert obs["y.vel"] == pytest.approx(-0.05)
+        assert obs["theta.vel"] == pytest.approx(0.2)
+
+    def test_odometry_zero_before_first_state(self):
+        robot = _connected_robot(use_front_camera=False)
+        obs = robot.get_observation()
+        assert all(obs[k] == 0.0 for k in robot._odom_ft)
+
+    def test_front_camera_decodes_to_configured_shape(self):
+        robot = _connected_robot(front_camera_width=64, front_camera_height=48)
+        raw = np.full((48, 64, 3), 128, dtype=np.uint8)
+        ok, jpeg = cv2.imencode(".jpg", raw)
+        assert ok
+        robot._video.GetImageSample.return_value = (0, jpeg.tobytes())
+        obs = robot.get_observation()
+        assert obs["front"].shape == (48, 64, 3)
+        assert obs["front"].dtype == np.uint8
+
+    def test_front_camera_resizes_native_frames(self):
+        robot = _connected_robot(front_camera_width=64, front_camera_height=48)
+        native = np.zeros((720, 1280, 3), dtype=np.uint8)
+        ok, jpeg = cv2.imencode(".jpg", native)
+        assert ok
+        robot._video.GetImageSample.return_value = (0, jpeg.tobytes())
+        assert robot.get_observation()["front"].shape == (48, 64, 3)
+
+    def test_front_camera_failure_returns_black_frame(self):
+        robot = _connected_robot(front_camera_width=64, front_camera_height=48)
+        robot._video.GetImageSample.return_value = (1, None)
+        frame = robot.get_observation()["front"]
+        assert frame.shape == (48, 64, 3)
+        assert frame.sum() == 0
+
+    def test_observation_matches_features(self):
+        robot = _connected_robot(front_camera_width=64, front_camera_height=48)
+        raw = np.zeros((48, 64, 3), dtype=np.uint8)
+        _, jpeg = cv2.imencode(".jpg", raw)
+        robot._video.GetImageSample.return_value = (0, jpeg.tobytes())
+        obs = robot.get_observation()
+        assert set(obs.keys()) == set(robot.observation_features.keys())
+
+    def test_raises_when_not_connected(self):
+        robot = _make_robot()
+        with pytest.raises(ConnectionError):
+            robot.get_observation()
+
+
+class TestDisconnect:
+    def test_disconnect_stops_motion(self):
+        robot = _connected_robot()
+        sport = robot._sport
+        robot.disconnect()
+        sport.StopMove.assert_called_once()
+        assert not robot.is_connected