refactor: Conditionally import tkinter and update local environment detection

src/streamlit_app.py

@@ -5,13 +5,19 @@ import warnings
 import shutil
 from io import BytesIO
 import tempfile
-import tkinter as tk
-from tkinter import filedialog
 import zipfile
 from pathlib import Path
 import glob
 import platform
 import subprocess
+
+# Conditionally import tkinter
+try:
+    import tkinter as tk
+    from tkinter import filedialog
+    TKINTER_AVAILABLE = True
+except ImportError:
+    TKINTER_AVAILABLE = False
 from main import (
     load_workbook_with_possible_passwords,
     copy_excel_file,
@@ -21,11 +27,7 @@ from main import (
 
 def is_running_locally():
     """Check if the app is running locally or in cloud environment"""
-    try:
-        import tkinter
-        return True
-    except ImportError:
-        return False
+    return TKINTER_AVAILABLE
 
 # Configure page
 st.set_page_config(