Closes the two gaps that forced CosmoMailServer's Phase D workarounds.
CASE WHEN expression support (searched form). Works in INSERT VALUES, SELECT list, WHERE, and nested in arithmetic. Simple form not added — no consumer needs it.
Function-call DEFAULT in CREATE TABLE. Non-literal DEFAULTs round-trip through the catalog as canonical SQL text (re-parsed at INSERT time). NEWID() added to the scalar dispatch alongside the existing GETUTCDATE() / GETDATE().
10 files changed, +462/-18; 254/254 driver tests pass (+10 new tests across Phase 11 and Phase 12).