[ty] Move all imports to file-level in type_ordering.rs
Move BindingContext, KnownBoundMethodType, KnownInstanceType,
MaterializationKind, ParameterKind, GenericContext, Specialization,
and NamedTupleSpec to top-level imports instead of using local `use`
statements or fully qualified `super::` paths.
https://claude.ai/code/session_01VfHXjU3ua6PKgWBHisG7TJ
