Professions.ByProgram was a `static readonly` field filtered on
DateTime.Today, so it evaluated once when the type first loaded. Two
consequences, both real:
- A long-running process kept serving the answer it computed at startup. A
mapping whose geldigVan fell after boot never appeared; one whose geldigTot
passed never disappeared.
- Both branches of StamdataFile.ActiveOn were unreachable from this caller,
which is why this table's validity window had no test at all. It is the
cleanest single explanation for Stamdata's 71.7% branch coverage (BL-005).
Adds ByProgramOn(DateOnly) — the peildatum as an argument, matching
StamdataTable.RowsOn which already parameterizes it — and makes ByProgram a
property delegating to it with today's date. Call sites (DiplomaRules) are
unchanged and keep the same behaviour, now with a current date.
ProfessionsTests covers both ActiveOn branches plus the regression itself:
the same date must give the same answer, a different date a different one.
Found by the testability pass (TE-009).
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
