Fix main.py

[JinWoong-Jung]

1. path_to_file_list (5~6 lines)
   a. Changed code : lines = open(path, 'r').read().split('\n')
   b. Why it is wrong before :
The original used open(path, 'w') (write mode) and returned a non-existent variable lines, causing runtime errors and preventing file reading.

2. Backslash escaping in process_file (13 line)
   a. Changed code : file = file.replace('', '\')
   b. Why it is wrong before
: The original file.replace('', '') did nothing, so backslashes were never escaped.

3. Wrong variable processed in loop (28 line)
   a. Changed code : german_file = process_file(german_file)
   b. Why it is wrong before
: The original mistakenly processed german_file into english_file again, overwriting the English path and ignoring the German path.

4. Incorrect JSON template keys (20 line)
   a. Changed code :
template_start = '{"English":"'
template_mid = '","German":"'
template_end = '"}'
   b. Why it is wrong before
: The original template used "German" twice, producing invalid or misleading JSON output.

5. Corrected JSON concatenation order (30 line)
   a. Changed code : processed_file_list.append(template_start + english_file + template_mid + german_file + template_end)
   b. Why it is wrong before
: The original concatenated the template pieces in an incorrect order, generating malformed JSON strings.

6. write_file_list file mode and writing logic (36~38 lines)
   a. Changed code :
with open(path, 'w') as f:
for file in file_list:
f.write(file + '\n')
   b. Why it is wrong before
: The original opened the file in read mode ('r') and wrote only '\n' without writing the actual strings.

7. Incorrect function arguments in main (46~48 lines)
   a. Changed code :
english_file_list = path_to_file_list(english_path), german_file_list = path_to_file_list(german_path)
processed_file_list = train_file_list_to_json(english_file_list, german_file_list)
   b. Why it is wrong before
: The original incorrectly called train_file_list_to_json(german_path) using file paths instead of file lists, causing wrong behavior and mismatched inputs.