fix: validate LoRA repo ID format

app.py

@@ -79,8 +79,8 @@ def generate(
             
             print("Model loaded!")
         
-        # Load LoRA if specified
-        if lora_repo and lora_repo != current_lora:
+        # Load LoRA if specified and valid
+        if lora_repo and isinstance(lora_repo, str) and lora_repo.strip() and "/" in lora_repo and lora_repo != current_lora:
             try:
                 print(f"Loading LoRA: {lora_repo}")
                 # Download LoRA from HF Hub