npr::rf::RadioRxCapture class final
#include <npr/phy/radio_rx_capture.hpp>

SI4463 RX capture helper that translates IRQ/FIFO state into packet callbacks.

Core idea:

Keep ISR minimal: IRQ edge timestamp is captured by ISR and consumed later.
Actual SPI/FIFO work stays in worker context (capture()), never in ISR.
Capture path is resilient to missed edges by combining IRQ-edge hint with periodic polling fallback.
Packet timestamp can be derived either from now_us or from sync-top reference (now_us - rx_sync_to_top_us), therefore consecutive packet timestamps are not guaranteed to be strictly monotonic.

Public types

enum class CaptureStatus: uint8_t { NoData = 0u, Captured, RadioError }: Capture operation status.
using PacketCallback = void(*)(void*user_data, const uint8_t*packet, size_t packet_size, uint64_t packet_time_us, bool rssi_valid, uint8_t rssi): Callback invoked for each fully captured packet.

auto capture(Si4463Device& radio, const RadioProfile& profile, NprDiagnostics& diagnostics, uint64_t now_us, PacketCallback callback, void* user_data) -> CaptureStatus: Polls radio IRQ/FIFO and emits zero or more packets through callback.
void notify_irq_edge(uint32_t edge_time_us32): ISR hook: stores first pending NIRQ falling-edge timestamp for precise RX timing reference.
void reset(uint64_t now_us, bool irq_pin_present): Resets capture state at runtime startup/recovery.

Polls radio IRQ/FIFO and emits zero or more packets through callback.

Returns	Capture status for current poll iteration.

ISR hook: stores first pending NIRQ falling-edge timestamp for precise RX timing reference.

Additional edges are coalesced until worker consumes the pending one.