Replaces the stub with the real sim per lanes/LANE-SIM.md round 1.
- grid + placement/remove/rotate/setRecipe, footprint rotation, bounds
- belts: 2 items/tile, 0.45 spacing enforced across the tile seam,
back-pressure, merges, belt<->machine handoff
- crafting: recipe buffers (2x in, stall at 4x out), edge-triggered jams
- bandwidth v1: gen vs draw, compression generates, brownout = gen/draw
scaling both craft progress and belt movement
- shipping + commission tracking
- output routing ranks belts by tracing the chain to its terminal machine,
so the demuxer's three outputs reach three different consumers without
splitters (see NOTES - biggest judgement call of the round)
18 tests. Measured 3,500 entities + 6,820 belt items at 0.42ms/tick (80x
realtime). Full M1 chain ships MELT at tick 1149 in both node and browser.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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