Rewrite parse_v2_bands to match the wire format the G522 firmware
actually emits: 3-byte header [direction_echo, slot_echo,
band_count_max], 5-byte stride [filter_type, gain_BE, freq_BE], and a
0..2 byte trailer that's opaque. band_count_max is the device's
max-bands capacity, not the populated-band count — bands are consumed
until <5 bytes remain or freq=0 marks end-of-bands.
Gain encoding switched from signed×step_db to offset-binary against
the gain bounds reported by getEQInfos, so raw 120 with steps=241 and
gain=[-6,6] decodes to 0 dB (flat) rather than +6 dB.
Add 0x16 to FILTER_TYPE_NAMES as peaking — that's the byte every G522
band carries at the textbook ISO third-octave centers (50, 125, 250,
500, 1000, 2500, 5000, 10000, 20000 Hz).
Previously the parser bailed because the 54-byte response wasn't a
clean multiple of 5, so the EQ panel never built.