I will clarify my statement by saying you can't do this on pfSense using the Snort GUI package.
You can potentially set something up if you go totally command-line with Snort and do not use the GUI at all. The GUI package cannot support inline IPS mode.
If you use the standalone binary, you can configure DAQ to use netmap IPS mode, but only if you are willing to use two actual physical interfaces and bridge them with a cross-over cable, or else put Snort and DAQ on a separate box that sits between your LAN and pfSense. None of this is easy to set up, and it would be something you would be on your own to configure and support.