forecastLines(def, lead) always took the param; what was missing was the
map from "this night is N nights away" to a lead. leadFor(nightsOut,
weekNights) is that map, linear onto forecastFor's documented 0..1 domain
so tonight is exact and the week's far end is lead 1. Tomorrow at a
five-night week reads 0.25 — 75% confidence, sustained band ~±8%.
hud.js is Lane A's; this only exports the argument.
The new assert pins the property that makes a band safe to print: it
RESOLVES. lo rises and hi falls monotonically onto the truth as the night
approaches, because the centre-wander is the same seeded draw at every
lead — so tomorrow's band always contains tonight's and the card never
jumps. Verified against a mutation that reseeds per lead (caught).
Its containment half is honestly decoration today and is labelled as
such in the test: 0.6-of-half-width wander means c±w never crosses v, so
deleting the clamps does not make it fail. Kept as a contract guard for a
future rewrite of band(), not counted as coverage of today's code.
Selftest 298/0/0.
8e23bf4702