PIR sensor outputs HIGH for too many seconds
Kind of a hack: Use a capacitor between transistor collector and RST pin. Try using 100nF as a starting value - might need to go higher.

Note that this assumes there is a clamping diode between RST and VCC on the ESP8266, as the capacitor would raise RST above VCC when the transistor turns off. Better don't use a large capacity value here - these diodes don't like too much current.