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/tasks/banana.py

@@ -18,16 +18,12 @@ from core.utils.scene_utils import deactivate_selected_prims
 from core.utils.transformation_utils import get_orientation
 from core.utils.visual_distractor import set_distractors
 from omegaconf import DictConfig
-from omni.isaac.core.materials import PreviewSurface
-from omni.isaac.core.prims import RigidContactView, XFormPrim
-from omni.isaac.core.scenes.scene import Scene
-from omni.isaac.core.tasks import BaseTask
-from omni.isaac.core.utils.prims import (
-    delete_prim,
-    get_prim_at_path,
-    is_prim_path_valid,
-)
-from omni.isaac.core.utils.stage import get_current_stage
+from core.compat import PreviewSurface
+from core.compat import RigidContactView, XFormPrim
+from core.compat import Scene
+from core.compat import BaseTask
+from core.compat import delete_prim, get_prim_at_path, is_prim_path_valid
+from core.compat import get_current_stage
 from omni.physx.scripts import particleUtils
 from pxr import Gf, PhysxSchema, Sdf, Usd, UsdGeom, UsdLux, UsdShade, Vt
 from scipy.spatial.transform import Rotation as R