ca32d865b2
C1: CreateBatch shadowed err with := in loop, causing partial commits on
failure. Fixed with named return and execErr loop variable.
H1: OrderBy concatenated raw into SQL query. Added whitelist validation.
H2: Organization.List dropped query args in SelectContext call.
H3: CourseRepository.Get wrapped sql.ErrNoRows without translating to
ErrNotFound, breaking the port contract.
Medium: Create now returns the created entity via Get; fixed prepared
statement leak in Organization.Create; unified time.Now() to UTC.