Auris v1.2.2

Add polyphase resampler

Introduce resampler.h implementing a Kaiser-windowed polyphase FIR resampler (RS_L=2, RS_M=3, RS_K=16) and a ResamplePolyphase() routine that converts int16 input to float output (normalized by 32768). Replace the previous linear Resample implementation and the WHISPER_RATE constant in steam_voice.cpp with an include of resampler.h and call to ResamplePolyphase(), improving sample-rate conversion from 24k to 16k using the new filter.