nx_netsync.nx

nx_netsync.nx -- the SOVEREIGN MULTIPLAYER NETCODE PART. nx_gamebench gap-queue rank 1 (networking-multiplayer, PARTIAL, blocks Freeciv-class and Veloren-class titles): the existing nx_lockstep / nx_rollback cores prove the MECHANISM on a synthetic toy stepper only -- nothing composed netcode with the CERTIFIED GAME PARTS. This part is that composition: deterministic lockstep sessions whose simulation IS nx_worldsim (the certified faction/economy world), whose snapshots ARE nx_gamesave files, so every property those parts certified carries onto the wire. THE INVARIANTS THIS PART EXISTS TO HOLD (each a gate tooth in nx_netsync_gate): 1. LOCKSTEP: only INPUTS cross the wire. Every peer runs the same deterministic sim; a session advances tick T only when commands from ALL peers for T are present. It STALLS rather than guesses -- advancing on partial input is the defining desync bug of lockstep netcode. 2. ARRIVAL-ORDER IMMUNE: commands may arrive shuffled, duplicated, or late; duplicates are idempotent, a CONFLICTING resend (same tick+peer, different command) is REFUSED loudly -- a peer cannot rewrite its committed input (the cheat/corruption door stays shut). 3. DESYNC DETECTABLE: ns_checksum walks the LIVE shared state independently of any save path (the GX-9 hollow-verifier law), so two peers comparing checksums localize a divergence to the exact tick it appears. 4. ROLLBACK-READY: whole-session snapshot/copy primitives make the confirmed-state + throwaway speculative-head pattern (fighting-game rollback) buildable on top without poisoning the confirmed input table. 5. DURABLE: the whole session arena is one flat i64 block -> gs_save/gs_load; a late joiner loads a snapshot file and resumes bit-identically (join-in-progress). Command wire format: one i64 per (tick,peer): 0 = no-op, else from*100000000 + to*1000000 + amt = a trade order applied through ws_trade (which conserves, clamps, refuses self-dealing -- the certified properties do the sanitizing; malformed decode fields die in ws_trade's guards). LIB ONLY -- no main() by ecosystem convention. license_tier: ORIGINAL expect_exit: 0