debug: add instrumentation to find crash location

app.py

@@ -5,14 +5,21 @@ PaperProf — Main Gradio entry point.
 import warnings
 warnings.filterwarnings("ignore")
 
-import random
-import gradio as gr
-import spaces
-
-from core.parser import extract_text
-from core.chunker import chunk_text
-from core.questioner import generate_question
-from core.evaluator import evaluate_answer
+try:
+    import random
+    import pathlib
+    import gradio as gr
+    import spaces
+    from core.parser import extract_text
+    from core.chunker import chunk_text
+    from core.questioner import generate_question
+    from core.evaluator import evaluate_answer
+    print("✅ All imports successful")
+except Exception as e:
+    import traceback
+    print(f"❌ Import error: {e}")
+    traceback.print_exc()
+    raise
 
 CSS = """
 /* Hide all Gradio chrome */
@@ -216,6 +223,7 @@ HEADER = """
 # UI
 # ---------------------------------------------------------------------------
 
+print("✅ Starting Gradio app...")
 with gr.Blocks(title="PaperProf", css=CSS) as demo:
 
     gr.HTML(CUSTOM_HTML)
@@ -346,5 +354,7 @@ document.addEventListener('DOMContentLoaded', function() {
         outputs=[feedback_box, correct_state, total_state, score_box],
     )
 
+print("✅ Gradio demo defined successfully")
+
 if __name__ == "__main__":
     pass