Wire OVPhysX preset into Allegro Repose direct task

Adds ``ovphysx`` to both preset classes in
``allegro_hand_env_cfg.py``:

* ``ObjectCfg`` — cube uses ``RigidObjectCfg`` (same as the ``physx``
  preset, since OVPhysX ships RigidObject support).
* ``PhysicsCfg`` — ``OvPhysxCfg()`` with defaults.

Validated with RSL-RL: 300 iterations clean on cuda:0.  Exercises both
the articulation (Allegro hand, 16 DOFs) and the rigid object (cube)
backends in the same scene.

Author: AntoineRichard

source/isaaclab_tasks/changelog.d/antoiner-feat-ovphysx_articulation.rst

@@ -0,0 +1,10 @@
+Added
+^^^^^
+
+* Added the ``ovphysx`` preset to ``Isaac-Repose-Cube-Allegro-Direct-v0``
+  (``ObjectCfg`` and ``PhysicsCfg`` in
+  :mod:`isaaclab_tasks.direct.allegro_hand.allegro_hand_env_cfg`), so the
+  task can be selected with ``presets=ovphysx`` against the OVPhysX
+  backend.  Exercises the OVPhysX :class:`~isaaclab_ovphysx.assets.Articulation`
+  (Allegro hand) and :class:`~isaaclab_ovphysx.assets.RigidObject` (cube)
+  in the same scene.

source/isaaclab_tasks/isaaclab_tasks/direct/allegro_hand/allegro_hand_env_cfg.py

@@ -5,6 +5,7 @@
 
 
 from isaaclab_newton.physics import MJWarpSolverCfg, NewtonCfg
+from isaaclab_ovphysx.physics import OvPhysxCfg
 from isaaclab_physx.physics import PhysxCfg
 
 import isaaclab.sim as sim_utils
@@ -56,6 +57,25 @@ class ObjectCfg(PresetCfg):
         actuators={},
         articulation_root_prim_path="",
     )
+    ovphysx = RigidObjectCfg(
+        prim_path="/World/envs/env_.*/object",
+        spawn=sim_utils.UsdFileCfg(
+            usd_path=f"{ISAAC_NUCLEUS_DIR}/Props/Blocks/DexCube/dex_cube_instanceable.usd",
+            rigid_props=sim_utils.RigidBodyPropertiesCfg(
+                kinematic_enabled=False,
+                disable_gravity=False,
+                enable_gyroscopic_forces=True,
+                solver_position_iteration_count=8,
+                solver_velocity_iteration_count=0,
+                sleep_threshold=0.005,
+                stabilization_threshold=0.0025,
+                max_depenetration_velocity=1000.0,
+            ),
+            mass_props=sim_utils.MassPropertiesCfg(density=400.0),
+            scale=(1.2, 1.2, 1.2),
+        ),
+        init_state=RigidObjectCfg.InitialStateCfg(pos=(0.0, -0.17, 0.56), rot=(0.0, 0.0, 0.0, 1.0)),
+    )
     default = physx
 
 
@@ -79,6 +99,7 @@ class PhysicsCfg(PresetCfg):
         num_substeps=2,
         debug_mode=False,
     )
+    ovphysx = OvPhysxCfg()
     default = physx