fix: IS 4.1.0 + Blackwell GPU compatibility fixes

- Add scipy Rotation scalar_first monkey-patch for older scipy (<1.11)
- Fix SimulationApp import to support both IS 4.x and 5.x
- Reuse task object across reset() calls to prevent duplicate prims
- Add _scene_initialized guard in set_up_scene() for repeated resets
- Cache arena_file_path to survive task_cfg.pop()
- Clean up collision groups before re-creating
- Switch to PathTracing renderer for clean output on Blackwell GPU

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

configs/simbox/de_plan_and_render_template.yaml

@@ -10,6 +10,7 @@ load_stage:
         rendering_dt: 1/30                 # Render update rate
         stage_units_in_meters: 1.0         # Stage unit scale
         headless: True                     # Headless mode (no GUI); set false for visual debugging
+        renderer: "PathTracing"            # PathTracing: higher quality, less noise on Blackwell
         anti_aliasing: 0                   # Anti-aliasing level
   layout_random_generator:                 # Scene randomization
     type: env_randomizer