- binds names via tree-sitter (default, namespace, named + alias, type-only),
keeps a statement when ANY bound name occurs outside it (word scan over
comments/strings included): under-delete is the safe direction, mirroring
the Java rule's asymmetry
- ESM caveat encoded in the policy: mixed live/dead statements are not
touched — removing a specifier would still drop the module's side effects
- side-effect imports and 'export .. from' re-exports are never candidates
- parser/ts became a folder (mod/extract/unused_imports) to keep the
4-entries-per-module rule; word_occurs shared via crate::parser
- java/rules/unused_imports now reuses the shared word scanner (DRY)
