This commit introduces support for uploading optional video files to products and image files to blog posts. Enhanced admin interfaces were added to preview these files directly. Also includes adjustments to GraphQL types and serializers to expose the new fields.
Replace WYSIWYG editor with Markdown editor across all relevant models and admin fields. Add utilities for rendering and stripping markdown. Adjust serializers, views, and templates to support markdown content. Introduce `PastedImage` model and upload endpoint for handling inline image uploads in markdown.
This change simplifies content formatting while enhancing flexibility with markdown support.
Fixes: 1) Correct default values and type handling in util constructors; 2) Resolve missing or ambiguous `cast` operations for dynamic typing in tests and views; 3) Address potential issues with fallback/default handling in middleware.
Extra: 1) Refactor test cases to ensure stricter adherence to typing hints and valid contracts; 2) Update docstrings to align with new type annotations; 3) Cleanup unused imports and add comments for improved maintainability.
