docs(rules): keep Java composition guidance in modern-java only

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

shared/rules/java/references/architecture-and-apis.md

@@ -7,5 +7,5 @@ Apply these rules when designing public APIs, service boundaries, or application
 * Authorize the specific resource and operation where data is accessed or changed. Preserve ownership and tenant scope across alternate paths and background work.
 * Bound payloads, page sizes, query complexity, and operation cost. Use pagination or streaming for potentially large results.
 * Keep domain decisions separate from transport, persistence, and framework wiring. Make dependencies explicit; use dependency injection for real lifecycle or substitution needs.
-* Prefer composition and small contracts at real boundaries. Avoid service locators, broad base classes, reflection, and wrappers without a concrete purpose.
+* Use small contracts at real boundaries. Avoid service locators.
 * Preserve existing API and serialization behavior unless the task requires a change. Treat changes to nullability, ordering, exception types, and collection mutability as compatibility changes.