- Add new `gitpull.php` page for manual git pull execution by administrators
- Remove automatic git pull on homepage visit to prevent unintended updates
- Include git pull link in admin navigation menu for easy access
- Secure interface with admin-only access and sudo credentials configuration
- Relocate hardness dropdown from left to right side of filter controls
- Change form submission behavior to update URL parameters directly
- Preserve selected hardness value on page reload
- Remove page parameter when hardness changes to reset pagination
- Improve visual alignment and spacing in filter interface
- Added hardness filter dropdown in problemset UI with options 1-8
- Implemented server-side hardness parameter validation and filtering
- Refactored query parameter handling to use $filter_params array
- Updated SQL queries to use parameter binding for both search and hardness filters
- Fixed pagination to include hardness parameter in URL
- Improved code organization by centralizing filter parameter management
