Fixes: 1) Resolved redundant lines and formatting inconsistencies across multiple files; 2) Corrected Collection typing imports and Optional replacements with union types (e.g., `str | None`);
Extra: Improved formatting and readability by consolidating single-line code sections and simplifying expressions.
Fixes: 1) Corrected `ForeignKey` type assertions across models; 2) Resolved typos and formatting inconsistencies in `.env` and README; 3) Fixed explicit boolean checks in user manager methods.
Extra: Updated type hints in multiple models, serializers, and views.
