nx_codon.nx

nx_codon.nx -- smallest re-targetable IR atom (silicon emission unit). Biology: codons are 3-nucleotide units that ribosomes translate into amino acids. Nishi codon is the smallest unit nx_ribosome (and the existing nxc2 codegen backends) translate into target machine code. ONE codon = ONE primitive operation emittable to any of the 14 nxc2 backends + the future SILICON_HDL backend. Per [[feedback-pathway-tropism-block-composition-location-agnostic]] vision: same .nx pathway runs on Cortex-M0+ (Thumb), x86_64, PTX (NVIDIA GPU), and Nishi silicon HDL -- because the underlying codons are the substrate's invariant. Codons compose into the rest of the cell's behavior. V1 ships: - sealed enum NxCodonOp (13 ops sufficient to express any cell) - struct NxCodon (op + operand_a + operand_b + target_hint) - struct NxCodonStream (ordered sequence of codons) - append + iterate + validate verbs Per Captain Moroni doctrine: codons are PURE DATA. They describe what to compute, not how -- the ribosome translates per-target. Substrate cannot embed offensive ops in codons because the op set is sealed (no DRONE_STRIKE / FIRMWARE_INJECT / etc).