Decoding

Decoding parses reads, probes the frame version, orients reads, aligns them to the marker template (turning indels into erasures), clusters and builds consensus, applies inner and outer Reed-Solomon decoding, and verifies the result against the superblock SHA-256 and Merkle root. Outcomes: SUCCESS; PARTIAL: only individually verified files are written; FAILURE: nothing is written. A decode report (--report) records stages, counters and the native backends that ran.