custom-longctx-lrfam-v6

v5's all-4096 + long-range reweight, plus:

• calendar and garch families (load curves / vol clustering)
• restored intermittent mass for count/retail-like windows
• richer multi-harmonic seasonality (incl. long calendar periods)
• scipy lfilter AR + larger chunk + fixed-length fast path (throughput)
• mild log-uniform scale diversity

Hypothesis: KOTH LCB rewards uniform skill across the rotating multi-domain pool, not peak skill on one family. Numpy + scipy, deterministic.