Add ComfyUI configuration for image generation with ROCm support

- Docker Compose setup with ROCm for RX 7800 XT (gfx1101)
- Auto-download script for SDXL models
- Basic SDXL workflow for testing
- Full documentation in README.md
- Update .gitignore to exclude model files (too large)

.gitignore

@@ -70,3 +70,19 @@ desktop.ini
 
 # Fichiers de configuration spécifiques à l'utilisateur
 *.local
+
+# ComfyUI - Modèles et outputs (trop volumineux)
+comfyui/models/checkpoints/*.safetensors
+comfyui/models/checkpoints/*.ckpt
+comfyui/models/vae/*.safetensors
+comfyui/models/vae/*.ckpt
+comfyui/models/loras/*.safetensors
+comfyui/models/loras/*.ckpt
+comfyui/output/*.png
+comfyui/output/*.jpg
+comfyui/output/*.jpeg
+comfyui/output/*.webp
+comfyui/input/*.png
+comfyui/input/*.jpg
+comfyui/input/*.jpeg
+comfyui/input/*.webp