feat: add ComfyUI_UltimateSDUpscale to custom nodes

Add ComfyUI_UltimateSDUpscale repository to support the ultimate-sd-upscale-production-v1 workflow. This provides high-quality image upscaling capabilities.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

arty.yml

@@ -63,6 +63,11 @@ references:
     description: "MusicGen and Stable Audio integration"
     essential: false
 
+  - url: https://github.com/ssitu/ComfyUI_UltimateSDUpscale.git
+    into: /workspace/ComfyUI/custom_nodes/ComfyUI_UltimateSDUpscale
+    description: "Ultimate SD Upscale for high-quality image upscaling"
+    essential: false
+
 # Environment profiles for selective repository management
 envs:
   # Production: Only essential components