feat(incremental): add Java declaration-coverage adapter

[schteff]

Summary

Right now every deleted or moved Java method blocks incremental updates, because Java has no declaration-coverage adapter. This adds one, so real deletions go through and generated members still block.

What changed

• Java is now a coverage language.
• Records, enums and annotation types count as classes (Java only; TypeScript enums are untouched).
• Anonymous, nested and local classes get their own scope, so their methods don't stand in for the outer class's methods.
• References like imports, method calls and annotations are no longer mistaken for declarations.
• Record components, enum constants and compact constructors still count as possible members.
• Lombok annotations that generate methods (like @Getter or @Data) block method deletions on the annotated type. @Slf4j, @NonNull and Spring's @Value don't.

Known limits

• Deleting a nested type, or a method on one, still stays unknown (the extractor only reads top-level types).
• Deleting one of several overloads stays unknown.
• Annotation processors other than Lombok aren't covered.

How I tested this

• Added 11 Java cases to test_symbol_evidence_matrix.test.mjs. The 7 "deleted" cases fail without the change.

• An older test used Java as its example of a language with no adapter, so I switched it to C#.

• Ran an incremental update that used to block on a Java project. It now publishes.

• pnpm lint

• pnpm --filter @understand-anything/core test

• pnpm test

• Manual smoke test

Versioning

• N/A, left for the maintainer to bump on merge