Fix path_to_file_list to read lines from file

[jungjun0708]

In main.py, I modified the path_to_file_list function.

Original code (lines 5–6):
li = open(path, 'w')
return lines

New code (lines 5–9):
lines: List[str] = []
with open(path, "r", encoding="utf-8") as f:
for line in f:
lines.append(line.rstrip("\n"))
return lines

Why the original code was wrong:

1. The file was opened in write mode ('w'), which truncates the file and does not read any contents.
2. The function never used the variable li and tried to return an undefined variable lines, which would raise a NameError.
3. Because of these issues, the function did not satisfy its own docstring (“Reads a file and returns a list of lines in the file”).