fix: IS 4.5.0 -> 5.0.0 migration — USD metadata, DomeLight, scene reuse

- Fix USD metersPerUnit/upAxis for IS 5.0.0 (no longer auto-compensated)
- Batch fix all Aligned_obj.usd, table, and art USD files with backups
- Fix DomeLight rotation to Z-axis only (prevent tilted environment map)
- Fix scene reuse across episodes (arena_file caching, task clearing, prim guard)
- Add migration tools: scan_usd_metadata.py, fix_usd_metadata.py
- Add migration guide: migerate/migerate.md
- Add nvidia-curobo to .gitignore
- Fix sort_the_rubbish config: obj_0 -> obj_1 (obj_0 does not exist)

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

workflows/simbox/core/configs/tasks/example/sort_the_rubbish.yaml

@@ -29,7 +29,7 @@ tasks:
     objects:
       -
         name: pick_object_left
-        path: task/sort_the_rubbish/non_recyclable_garbage/obj_0/Aligned_obj.usd
+        path: task/sort_the_rubbish/non_recyclable_garbage/obj_1/Aligned_obj.usd
         target_class: RigidObject
         dataset: oo3d
         category: bottle