feat: migrate omni.isaac.* imports to isaacsim.* via compat layer

- Add core/compat.py: compatibility module with try/except imports
  supporting both IS 4.x (omni.isaac.*) and IS 5.x+ (isaacsim.*)
- Migrate 152 imports across 47 files from direct omni.isaac.* to core.compat
- Handle class renames: RigidPrim→SingleRigidPrim, GeometryPrim→SingleGeometryPrim,
  XFormPrim→SingleXFormPrim, Articulation→SingleArticulation (aliased for compatibility)
- Add migerate/migrate_imports.py: automated migration script for future use
- Leave debug_draw and env_loader try/except imports as-is

This eliminates ~100 deprecation warnings from our code on IS 5.0,
and future-proofs for IS 6.x when old APIs may be removed.

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

workflows/simbox/core/compat.py

@@ -0,0 +1,198 @@
+"""
+Isaac Sim 4.x / 5.x API compatibility layer.
+
+IS 5.0 renamed all `omni.isaac.*` modules to `isaacsim.*`.
+This module provides unified imports that work across both versions.
+Import from here instead of directly from omni.isaac.* or isaacsim.*.
+"""
+
+# ===== Core =====
+try:
+    from isaacsim.core.api import World
+except ImportError:
+    from omni.isaac.core import World
+
+# ===== Controllers =====
+try:
+    from isaacsim.core.api.controllers.base_controller import BaseController
+except ImportError:
+    from omni.isaac.core.controllers import BaseController
+
+# ===== Tasks =====
+try:
+    from isaacsim.core.api.tasks.base_task import BaseTask
+except ImportError:
+    from omni.isaac.core.tasks import BaseTask
+
+# ===== Robots =====
+try:
+    from isaacsim.core.api.robots.robot import Robot
+except ImportError:
+    from omni.isaac.core.robots.robot import Robot
+
+# ===== Prims (class names changed in IS 5.x) =====
+try:
+    from isaacsim.core.prims import SingleXFormPrim as XFormPrim
+except ImportError:
+    from omni.isaac.core.prims import XFormPrim
+
+try:
+    from isaacsim.core.prims import SingleRigidPrim as RigidPrim
+except ImportError:
+    from omni.isaac.core.prims import RigidPrim
+
+try:
+    from isaacsim.core.prims import SingleGeometryPrim as GeometryPrim
+except ImportError:
+    from omni.isaac.core.prims import GeometryPrim
+
+try:
+    from isaacsim.core.api.sensors.rigid_contact_view import RigidContactView
+except ImportError:
+    from omni.isaac.core.prims import RigidContactView
+
+# ===== Articulations =====
+try:
+    from isaacsim.core.prims import SingleArticulation as Articulation
+except ImportError:
+    from omni.isaac.core.articulations.articulation import Articulation
+
+# ===== Objects =====
+try:
+    from isaacsim.core.api.objects.cylinder import VisualCylinder
+except ImportError:
+    from omni.isaac.core.objects.cylinder import VisualCylinder
+
+try:
+    from isaacsim.core.api.objects import cuboid, sphere
+except ImportError:
+    from omni.isaac.core.objects import cuboid, sphere
+
+# ===== Materials =====
+try:
+    from isaacsim.core.api.materials import PreviewSurface
+except ImportError:
+    from omni.isaac.core.materials import PreviewSurface
+
+try:
+    from isaacsim.core.api.materials import OmniPBR
+except ImportError:
+    try:
+        from omni.isaac.core.materials import OmniPBR
+    except ImportError:
+        from omni.isaac.core.materials.omni_pbr import OmniPBR
+
+try:
+    from isaacsim.core.api.materials import OmniGlass
+except ImportError:
+    from omni.isaac.core.materials import OmniGlass
+
+# ===== Scenes =====
+try:
+    from isaacsim.core.api.scenes.scene import Scene
+except ImportError:
+    from omni.isaac.core.scenes.scene import Scene
+
+# ===== Utils: prims =====
+try:
+    from isaacsim.core.utils.prims import (
+        get_prim_at_path,
+        create_prim,
+        delete_prim,
+        is_prim_path_valid,
+    )
+except ImportError:
+    from omni.isaac.core.utils.prims import (
+        get_prim_at_path,
+        create_prim,
+        delete_prim,
+        is_prim_path_valid,
+    )
+
+# ===== Utils: transformations =====
+try:
+    from isaacsim.core.utils.transformations import (
+        get_relative_transform,
+        pose_from_tf_matrix,
+        tf_matrix_from_pose,
+        tf_matrices_from_poses,
+    )
+except ImportError:
+    from omni.isaac.core.utils.transformations import (
+        get_relative_transform,
+        pose_from_tf_matrix,
+        tf_matrix_from_pose,
+        tf_matrices_from_poses,
+    )
+
+# ===== Utils: stage =====
+try:
+    from isaacsim.core.utils.stage import (
+        get_current_stage,
+        add_reference_to_stage,
+    )
+except ImportError:
+    from omni.isaac.core.utils.stage import (
+        get_current_stage,
+        add_reference_to_stage,
+    )
+
+# ===== Utils: xforms =====
+try:
+    from isaacsim.core.utils.xforms import get_world_pose
+except ImportError:
+    from omni.isaac.core.utils.xforms import get_world_pose
+
+# ===== Utils: types =====
+try:
+    from isaacsim.core.utils.types import ArticulationAction
+except ImportError:
+    from omni.isaac.core.utils.types import ArticulationAction
+
+# ===== Utils: viewports =====
+try:
+    from isaacsim.core.utils.viewports import set_camera_view
+except ImportError:
+    from omni.isaac.core.utils.viewports import set_camera_view
+
+# ===== Utils: semantics =====
+try:
+    from isaacsim.core.utils.semantics import add_update_semantics
+except ImportError:
+    from omni.isaac.core.utils.semantics import add_update_semantics
+
+# ===== Utils: string =====
+try:
+    from isaacsim.core.utils.string import find_unique_string_name
+except ImportError:
+    from omni.isaac.core.utils.string import find_unique_string_name
+
+# ===== Utils: stage units =====
+try:
+    from isaacsim.core.utils.stage import get_stage_units
+except ImportError:
+    from omni.isaac.core.utils.stage import get_stage_units
+
+# ===== Utils: extensions =====
+try:
+    from isaacsim.core.utils.extensions import enable_extension
+except ImportError:
+    from omni.isaac.core.utils.extensions import enable_extension
+
+# ===== Utils: nucleus =====
+try:
+    from isaacsim.storage.native import get_assets_root_path as nucleus_path
+except ImportError:
+    from omni.isaac.core.utils.nucleus import get_assets_root_path as nucleus_path
+
+# ===== Sensor: Camera =====
+try:
+    from isaacsim.sensors.camera import Camera
+except ImportError:
+    from omni.isaac.sensor import Camera
+
+# ===== SimulationApp =====
+try:
+    from isaacsim import SimulationApp
+except ImportError:
+    from omni.isaac.kit import SimulationApp