-- Migration 034: model_snapshots.factor_inputs — FREEZE THE FACTOR INPUTS (Fix A5).
--
-- A re-audit that joins context tables to a past grade RECONSTRUCTS what the
-- context probably was. This column carries what the grader ACTUALLY read, so a
-- row becomes independently checkable.
--
-- INPUTS, NOT OUTPUTS. It stores the raw values (spray shares, positional OAA,
-- pitcher hard-hit rate, platoon split counts, handedness) and NOT the resulting
-- multiplier. A stored multiplier can only be compared to itself; stored inputs
-- can be re-run through hitsFactors and checked.
--
-- A SEPARATE COLUMN, not extra keys inside `features`: champion-ablation.js
-- iterates every key of `features` for its residual scan, so widening it would
-- silently enlarge that multiple-comparisons denominator.
--
-- NULLABLE and populated only on `hits` rows with a factor context, so the
-- storage cost is bounded. Adding a nullable column is metadata-only in
-- Postgres — no table rewrite — which matters while this database sits over its
-- free-tier size cap.
ALTER TABLE model_snapshots ADD COLUMN IF NOT EXISTS factor_inputs jsonb;

COMMENT ON COLUMN model_snapshots.factor_inputs IS
  'Fix A5: raw inputs the hits factors read at grade time (never the multiplier). Recompute via factorFreeze.recompute().';