fix(CVG-45): centralize duplicate mappers in @cv/core, route api modules through local wrappers
DI runtime fix: NestJS uses class identity for injection. SkillService et al expected core's SkillMapper class but api was registering its own duplicate, causing UnknownDependenciesException at boot. Solution: delete api duplicate mapper files (skill/level/role/company/application/cv-template/cv/education/institution/employment/organization/vacancies + sub-entities), export from core barrels, route api Module imports through api-local wrappers (which add resolvers/dataloaders) instead of core's bare modules.