Spaces: remove Dockerfile, guard Streamlit execution to avoid bare-mode

Dockerfile

@@ -1,9 +0,0 @@
-FROM pytorch/pytorch:latest
-
-WORKDIR /app
-
-COPY . .
-
-RUN pip install -r requirements.txt
-
-CMD [ "streamlit", "run", "app.py" ]

app.py

@@ -139,7 +139,6 @@ def run_streamlit_ui():
                     "upload then remove the artifacts.")
 
 
-if __name__ == "__main__":
-    # Streamlit Spaces run the file with `streamlit run app.py`
-    # So keep a safe guard for direct execution as well
+# Only run when executed by Streamlit runner
+if getattr(st, "runtime", None) and st.runtime.exists():
     run_streamlit_ui()