#3100 Community report: Apple M1 Max 64 GB (Metal streaming) — tuning matrix neutral

Description

Settings/tuning matrix at ~160 and 35,778 tokens: ROUTE_TAIL_SKIP 0/7/10, --kv k8v4 and prompt chunk 2048/4096 are all neutral (decode ~21 tok/s, cold prompt ~245-276 tok/s) because the arena holds 12943 of 24576 ranked experts resident. README + per-run results.json + engine start-up excerpt.

## Title
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Issue: Resolves # 

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