Fix critical startup order bug - ensure ComfyUI setup before model downloads

Previously, download_models() created empty directories that caused ensure_setup()
to incorrectly skip cloning ComfyUI, resulting in 'main.py not found' errors.
This fix reorders the startup sequence to clone ComfyUI first, then download
models into the proper directories.

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

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

app.py

@@ -742,16 +742,16 @@ if __name__ == "__main__":
     log_startup("=" * 50)
     
     try:
-        # Step 1: Download all models first
-        log_startup("🎨 Downloading Authenticity Stack models...")
-        download_models()
-        manager.models_downloaded = True
-        
-        # Step 2: Ensure environment (cloning repos) is set up
+        # Step 1: Ensure environment (cloning repos) is set up
         if not manager.ensure_setup():
             log_startup("❌ Initial setup failed", "ERROR")
             raise RuntimeError("Setup failed")
         
+        # Step 2: Download all models after ComfyUI is set up
+        log_startup("🎨 Downloading Authenticity Stack models...")
+        download_models()
+        manager.models_downloaded = True
+        
         # Step 3: Start server
         log_startup("🔧 Starting ComfyUI server...")
         if not manager.start_server():