Fix diskpart script encoding for Windows compatibility

- Use cp1252 (Windows ANSI) encoding instead of UTF-8 for diskpart script
- Diskpart expects ANSI encoding and may not read UTF-8 files correctly
- Should resolve issue where diskpart window remains blank
- File creation and reading now use consistent Windows-compatible encoding

usb_creator_gui.py

@@ -328,14 +328,14 @@ exit
                 candidate_path = os.path.join(temp_dir, script_filename)
                 self.status.emit(f"Directory {i+1}: Trying to create script at {candidate_path}")
                 
-                # Try to write script file with explicit encoding
-                with open(candidate_path, 'w', encoding='utf-8') as script_file:
+                # Try to write script file with Windows ANSI encoding (diskpart expects this)
+                with open(candidate_path, 'w', encoding='cp1252') as script_file:
                     script_file.write(diskpart_script)
                 
                 # Verify file exists and is readable
                 if os.path.exists(candidate_path) and os.path.isfile(candidate_path):
                     # Verify we can read the file back
-                    with open(candidate_path, 'r', encoding='utf-8') as verify_file:
+                    with open(candidate_path, 'r', encoding='cp1252') as verify_file:
                         content = verify_file.read()
                         if content.strip():  # File has content
                             script_path = candidate_path