Synchronize bilingual documentation when StaticPHP v3 user-facing or developer-facing documentation must change. Use when adding, modifying, deprecating, or removing documented features, CLI commands/options, environment variables, configuration formats, public APIs/extension points, workflows, installation requirements, migration guidance, or user-visible behavior. Do not use solely for internal implementation changes, package/library additions, or build bug fixes unless they change documented behavior or require updating existing docs.