Package options provides a shared mechanism for applying functional options
across all SDK entry points. It enforces a single nil-option rule: nil
entries in an option list are silently ignored.
func Apply[T any, O ~func(*T)](target *T, opts []O)
Apply folds opts into target in order, skipping nil entries.
O is constrained to any named function type whose underlying type is
func(*T), so callers write options.Apply(&cfg, opts) and both type
parameters are inferred.