Propagates the new baseline (176 passed, 0 skipped) established by the
GradientCheck_Hessian implementation across all documentation files that
previously referenced the stale counts (174/173/170 + 1-2 skips).
Files updated: CLAUDE.md, doc/api/tests.md, doc/contributing.md,
doc/getting-started.md, doc/math/novelty-statement.md,
doc/math/validation.md, doc/math/validation-protocol.md, scripts/try_it.sh
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>