Added a new file theme-light.json for the light theme and defined it in Monaco editor as lightTheme. Created state management for theme changes and stored the selected theme in local storage. Added a dropdown to toggle between themes.

This PR addresses a bug #523 in the job sorting functionality where sorting by maxSalary was not correctly pushing non-disclosed salary jobs to the end. The fix ensures that nulls: 'last' is applied only when sorting by maxSalary, while other fields (e.g., postedAt) use standard sorting logic without nulls. This resolves errors encountered when sorting by non-salary fields.