test(cleaner): ✅ add tests for cleaner module

remove also comments in `test_mail_reader.py` that didn't follow package conventions

tests/test_mail_reader.py

@@ -355,9 +355,6 @@ def test_connect_to_mailbox_invalid_credentials(
         assert "Connection established successfully." not in caplog.messages
 
 
-###############################
-# fetch_log_messages(account) #
-###############################
 def test_fetch_log_messages_returns_messages(make_mock_account):
     """Returns the .all() of the Logs folder."""
     mail_inline = Message(subject="mail1", text_body="text1")
@@ -376,9 +373,6 @@ def test_fetch_log_messages_folder_path(make_mock_account):
     account.msg_folder_root.__truediv__.assert_called_once_with("Logs")
 
 
-##############################
-# extract_log_lines(content) #
-##############################
 def test_extract_log_lines_split_and_clean(original_log_dir: Path):
     r"""Split content, strips '\r\n', removes empty lines."""
     file = original_log_dir / "CR_20260727110008.txt"
@@ -425,9 +419,6 @@ def test_extract_log_lines_crlf():
         assert "\r" not in line
 
 
-#############################
-# extract_logs_from_mails() #
-#############################
 def test_extract_logs_from_mails_with_attachment(original_log_dir: Path):
     """Accumulates log lines from attachment mails."""
     # create mail with attachments