Fix session state initialization error

- Centralized session state initialization at the beginning of the app
- Fixed AttributeError with processed_document_active
- Removed redundant initialization code
- Streamlined state management for better reliability

app.py

@@ -1195,11 +1195,14 @@ with main_tab3:
     """)
 
 with main_tab1:
-    # Initialize session states if needed
+    # Initialize all session state variables in one place at the beginning
+    # This ensures they exist before being accessed anywhere in the code
     if 'auto_process_sample' not in st.session_state:
         st.session_state.auto_process_sample = False
     if 'sample_just_loaded' not in st.session_state:
         st.session_state.sample_just_loaded = False
+    if 'processed_document_active' not in st.session_state:
+        st.session_state.processed_document_active = False
         
     # Use uploaded_file or sample_document if available
     if 'sample_document' in st.session_state and st.session_state.sample_document is not None:
@@ -1288,13 +1291,9 @@ with main_tab1:
                     # Rerun to reset the page
                     st.rerun()
         
-        # Check if we need to auto-process a sample document
-        if 'auto_process_sample' not in st.session_state:
-            st.session_state.auto_process_sample = False
+        # auto_process_sample is already initialized at the top of the function
         
-        # Initialize processed_document_active if needed
-        if 'processed_document_active' not in st.session_state:
-            st.session_state.processed_document_active = False
+        # processed_document_active is already initialized at the top of the function
             
         # Results section - process if button clicked or auto-process flag is set
         process_now = process_button or st.session_state.auto_process_sample
@@ -2060,12 +2059,8 @@ with main_tab1:
                     # Close document content div
                     st.markdown('</div>', unsafe_allow_html=True)
                 
-                # Initialize processed_document_active in session state if needed
-                if 'processed_document_active' not in st.session_state:
-                    st.session_state.processed_document_active = True
-                else:
-                    # Set to True when new document is processed
-                    st.session_state.processed_document_active = True
+                # Set processed_document_active to True when a new document is processed
+                st.session_state.processed_document_active = True
                 
                 # Add CSS for styling close buttons
                 st.markdown("""