cfb89dd72f
Track locals moved by value into struct fields, let bindings, or return
values so Array/Drop types are not freed while still owned by the target.
- hir_lower: movedOutLocals + markMovedOutFromAst + shouldSkipDrop
- Nexus: drop zeroing workaround; free headers after each request
- examples/move_field.bux regression for Box { items: arr }