Add per-year unpredictable-event floor (FOMC/NFP/CPI/GDP/VIX/NASDAQ): 10,014 -> 12,838 q; every year 25-51% unpredictable

Restore quarterly recurrent cadence: 5,443 -> 10,014 q, even ~280-312 recurrent/year + black swans

Replace per-year parquet with unified string schema

Fix per-year parquet schema (unify 17 cols, string types) for by_year splits

Add per-year parquet + by_year config (28 year splits)

Add historical financial forecasting MCQ (5,443 q; forecast/blind/revealed)