fix(GRO-1350): add missing coatType and petSizeCategory to buildPet defaults

PetRow (pets.$inferSelect) now includes these nullable columns after
the GRO-1174 migration, but buildPet's defaults were never updated.
Adding null defaults fixes the typecheck failure in CI.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/db/src/factories.ts

@@ -99,6 +99,8 @@ export function buildPet(overrides: Partial<PetRow> & { clientId: string }): Pet
     cutStyle: null,
     shampooPreference: null,
     specialCareNotes: null,
+    coatType: null,
+    petSizeCategory: null,
     customFields: {},
     photoKey: null,
     photoUploadedAt: null,