CustomLR1110::startReceive() passed RADIOLIB_LR11X0_IRQ_PREAMBLE_DETECTED
(1<<4 = 16) as RadioLib's first argument, which is the RX *timeout*, not an
IRQ mask. At the LR11x0's 30.52us tick that armed the receiver for ~488us, so
it dropped out of RX before any packet could arrive and the node received
nothing at all -- while transmitting normally.
Symptoms on a SenseCAP T1000-E: tx_air_secs rising, rx_air_secs stuck at 0,
recv_errors 0, and the noise floor pinned at the -120 clamp because
getCurrentRSSI() never sampled a live receiver.
Pass RADIOLIB_LR11X0_RX_TIMEOUT_INF (continuous RX), which is what
LR11x0::startReceive() itself uses, keeping the PREAMBLE_DETECTED flag in the
reported IRQ flags as intended.
Introduced in ea5d7c8b ("LR1110: add PREAMBLE_DETECTED to reported irq flags").
Verified on two T1000-E units: with only the repeater fixed it began receiving
(last_rssi -29, SNR 17.0) while the unfixed companion stayed deaf; fixing both
brought up the link in each direction.
