refactor: replace UsageCallback closure with InnerGraphUsageOperation enum
Replace the closure-based UsageCallback pattern in InnerGraphPlugin::on_usage
with an InnerGraphUsageOperation enum for better performance and code clarity.
Changes:
- Add InnerGraphUsageOperation enum with three variants:
- PureExpression(DependencyRange)
- ESMImportSpecifier(usize)
- URLDependency(usize)
- Update on_usage to accept enum instead of closure
- Update infer_dependency_usage to match on enum variants
- Update 11 call sites across plugin.rs, esm_import_dependency_parser_plugin.rs,
and url_plugin.rs