Persist Atom Distributions per Year using the 7-pack

[Gorm2303]

Given atom values differ across Monte Carlo paths
When persisting a Tier 1 run
Then each stored atom is persisted as a distribution summary per year using the 7 percentiles (p5/p10/p25/p50/p75/p90/p95)

Stored distributions (per year)

capital (end-of-year snapshot distribution)

deposit_year (yearly total distribution)

return_year (yearly credited P&L total distribution)

withdraw_year (yearly total distribution)

tax_year (yearly total distribution)

fee_year (yearly total distribution)

inflation (end-of-year multiplier; store as scalar if deterministic, distribution if stochastic)

Acceptance criteria

For each year and each stored atom metric, DB contains values for p5/p10/p25/p50/p75/p90/p95

Deterministic metrics are stored consistently (either as a scalar + documented, or as a distribution with identical percentile values)