Add max files limit to HF dataset download

Use HF cache for dataset downloads instead of custom local_dir

Fix src/__init__.py: export download_hf_dataset instead of removed LoRATrainer

Rewrite Tab 3 to wire real training pipeline with HF dataset support

Fix DiT initialization: pass model name only, not full path

Fix TypeError: pass Path object to ensure_main_model, not string

Fix syntax error: close unterminated docstring in _load_models

Use official ACE-Step model downloader for automatic model downloads

Fix engine initialization and audio I/O components

Deploy ACE-Step Custom Edition with bug fixes