fix: correct cache directory path construction in cleanup function

Fix bash string substitution to replace all forward slashes with
double hyphens when constructing HuggingFace cache paths.

Changed from: ${repo_id/\//-}  (replaces first / with single -)
Changed to:   ${repo_id//\/--} (replaces all / with --)

This fixes the "Cache directory not found" warning when using the
--cleanup flag with repositories that have slashes in their names
(e.g., black-forest-labs/FLUX.1-schnell).

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

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

artifact_huggingface_download.sh

@@ -704,7 +704,7 @@ cleanup_unused_cache_files() {
     local comfyui_dir="$3"
 
     # Find the latest snapshot directory for this repo
-    local repo_cache_dir="${cache_dir}/models--${repo_id/\//-}"
+    local repo_cache_dir="${cache_dir}/models--${repo_id//\/--}"
     if [[ ! -d "$repo_cache_dir" ]]; then
         print_warning "Cache directory not found for $repo_id"
         return 1