Play Framework

test(validation): add tests for the untested Check classes (PF-138)

Cover the ~15 previously untested validation Check classes that run on
every form submission: Range/Min/Max, MinSize/MaxSize, Equals, InFuture/
InPast, Required, Email, IsTrue, Match, CheckWith, and ValidCheck's
recursive object-graph validation. Annotation-driven checks are configured
with real annotations read via reflection so configure() is exercised too.
Date checks are made deterministic by pinning the reference via the
annotation value(). UniqueCheck's DB-backed path is integration-scope; only
its null no-op and configure() are unit-tested. Test-only; no prod changes.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>