Add boot diagnostics to trace silent startup failure

app.py

@@ -6,22 +6,36 @@ A comprehensive music generation system with three main interfaces:
 3. LoRA Training Studio
 """
 
-import gradio as gr
-import torch
-import numpy as np
-from pathlib import Path
-import json
-from typing import Optional, List, Tuple
-import spaces
-
-from src.ace_step_engine import ACEStepEngine
-from src.timeline_manager import TimelineManager
-from src.lora_trainer import download_hf_dataset
-from src.audio_processor import AudioProcessor
-from src.utils import setup_logging, load_config
-from acestep.training.dataset_builder import DatasetBuilder
-from acestep.training.configs import LoRAConfig, TrainingConfig
-from acestep.training.trainer import LoRATrainer as FabricLoRATrainer
+import sys
+print("[BOOT] app.py starting imports...", flush=True)
+
+try:
+    import gradio as gr
+    print("[BOOT] gradio OK", flush=True)
+    import torch
+    import numpy as np
+    from pathlib import Path
+    import json
+    from typing import Optional, List, Tuple
+    import spaces
+    print("[BOOT] stdlib + spaces OK", flush=True)
+
+    from src.ace_step_engine import ACEStepEngine
+    from src.timeline_manager import TimelineManager
+    from src.lora_trainer import download_hf_dataset
+    from src.audio_processor import AudioProcessor
+    from src.utils import setup_logging, load_config
+    print("[BOOT] src imports OK", flush=True)
+
+    from acestep.training.dataset_builder import DatasetBuilder
+    from acestep.training.configs import LoRAConfig, TrainingConfig
+    from acestep.training.trainer import LoRATrainer as FabricLoRATrainer
+    print("[BOOT] acestep.training imports OK", flush=True)
+except Exception as e:
+    print(f"[BOOT] IMPORT FAILED: {e}", flush=True)
+    import traceback
+    traceback.print_exc()
+    sys.exit(1)
 
 # Setup
 logger = setup_logging()