WP1 wrote these against its interim VirtualTag-only collision rule; WP4a replaced it
with the broader UnsEffectiveNameCollision rule. Neither test-sweep scope covered these
two Configuration.Tests files, so the assertions went stale. Configuration.Tests 107/107.
Filter ExternalIdReservations to WHERE ReleasedAt IS NULL so
DraftSnapshot.ActiveReservations matches its documented semantics and
ValidateReservationPreflight cannot emit spurious BadDuplicateExternalIdentifier
errors from already-released rows. Adds a focused unit test seeding one active
and one released reservation and asserting only the active row is returned.