feat(check): java public-class ⇄ file-name mismatch — layout finding with a ready jmove mv repair

- parser::java::class_name: exactly-one-public-top-level-type rule
  (package-info/module-info and 0-or-2-public files skipped)
- check gains name_mismatches[] (JSON, omitted when clean) + human lines;
  exit 2 covers both kinds; fix engine untouched by design — a file rename
  is not a byte edit, and mv keeps the FQN so no imports change
- output split into output/{mod,check} to stay under the 250-line rule
- e2e: reports Bad.java, stays quiet on Good.java, suggested rename makes
  check pass and preserves the file bytes

docs/EXAMPLES.md

@@ -42,7 +42,7 @@ Rewrites happen first, the rename last; any failure rolls everything back.
 
 ```console
 $ jmove check
-check: no broken imports found
+check: no findings
 ```
 
 When something does point at nothing, `check` prints one line per broken