Each square in a $5\times 5$ grid is either filled or empty, and has up to eight adjacent neighboring squares, where neighboring squares share either a side or a corner. The grid is transformed by the following rules:

• Any filled square with one or two filled neighbors remains filled.
• Any empty square with exactly two filled neighbors becomes a filled square.
• All other squares remain empty or become empty.

Suppose the $5\times 5$ grid has a border of empty squares surrounding a $3\times 3$ subgrid (meaning only the $3\times 3$ central cells can be configured, and border cells are fixed to empty). How many initial configurations will lead to a transformed grid consisting of a single filled square in the center after a single transformation? (Rotations and reflections of the same configuration are considered different.)