d512268526
Add the three missing VDES decoder components per ITU-R M.2092-1: - turbo.rs: Turbo FEC decoder with dual 8-state RSC constituent encoders, BCJR/MAP iterative decoding (8 iterations), QPP interleaver, and rate-1/2 depuncturing - crc.rs: CRC-16-CCITT validation (poly 0x1021, init 0xFFFF) for decoded link-layer frames - link_layer.rs: Structured parsing of M.2092-1 link-layer frames (Messages 0-6) including station addressing, ASM identification, geographic bounding boxes, and ACK/NACK reporting The main decode pipeline now attempts turbo decoding first with CRC validation, falls back to Viterbi when turbo fails, and reports crc_ok=true when either path validates. 27 tests covering all new modules. https://claude.ai/code/session_01SJSN7cv3zoL1xNcb8ex2zY Signed-off-by: Claude <noreply@anthropic.com>