The mock's DIFF service normalised numeric values with Number(), so a SAS
special missing (".b") became NaN and was emitted as null - the value vanished
from the DIFF screen even though the staged data held it.
Real Data Controller writes the DIFF with missing=STRING, whose format maps ._
and .a-.z to a string and leaves a bare "." as null (see the bart format in
mp_jsonout.sas). The mock now mirrors that, so a special missing survives into
the DIFF. Special missings are numeric-only, so the guard sits in the numeric
branch of normVal.
Also adds cypress/clips/special-missings-clip.cy.ts - the recording script for
the companion demo clip. It lives outside cypress/e2e so the default spec
pattern does not pick it up in CI.
dc
d124ce3b36