You don't get to choose an arbitrary "lived in status" or "worked in status." Your residence is where you actually live. Your work location is where you actually work. If you live and work in DC, you are a DC resident and you pay DC tax on the money that you earn for working in DC. If you move from Philadelphia to DC you are no longer a resident of Philadelphia. The location of your employer's headquarters makes no difference.
For this year, 2025, you will be a part-year resident of Philadelphia and a part-year resident of DC, so you will have to file part-year resident tax returns in both places. It's not clear where you actually worked up until now, prior to moving. If you worked in DC you will have to pay DC tax on the income that you earned there, even you were still a Philadelphia resident.
