Fixes: 1) Correct default manager assignment in `Product` model; 2) Address potential division by zero in `AbsoluteFTPStorage`; 3) Ensure proper exception handling for missing `order` attributes in CRM gateway methods; 4) Rectify inaccurate string formatting for `Transaction` `__str__` method.
Extra: Refactor various minor code style issues, including formatting corrections in the README, alignment in the emailing utility, and suppressed pycharm-specific inspections; clean up unused imports across files; enhance error messaging consistency.
Fixes: 1) Correct `urlsafe_base64_encode` decoding logic in tests; 2) Fix queryset access issues in resolvers; 3) Address missing or incorrect imports across multiple files.
Extra: Improve code readability with consistent naming and formatting; Add `# noinspection` annotations to suppress IDE warnings; Update `pyproject.toml` to exclude `drf.py` in MyPy checks.
