Fix HF_TOKEN handling to prevent interactive password prompt

Co-authored-by: matheus-rech <71096630+matheus-rech@users.noreply.github.com>

app.py

@@ -45,13 +45,13 @@ if not hf_token:
     print("⚠️ WARNING: HF_TOKEN environment variable not set!")
     print("⚠️ Some features may not work. Please set HF_TOKEN in Space settings.")
     hf_token = None  # Allow app to start, but model loading will fail gracefully
-
-# Login to Hugging Face Hub
-try:
-    from huggingface_hub import login
-    login(token=hf_token, add_to_git_credential=False)
-except Exception as e:
-    print(f"⚠️ Could not login to HF Hub (non-critical): {e}")
+else:
+    # Login to Hugging Face Hub (only if token is provided)
+    try:
+        from huggingface_hub import login
+        login(token=hf_token, add_to_git_credential=False)
+    except Exception as e:
+        print(f"⚠️ Could not login to HF Hub (non-critical): {e}")
 
 # Load SAM 3 Model
 print("🧠 Loading SAM 3 Model...")