- WriteBuffer<T> with offer/offerBatch/drain and backpressure (all tests green) - ExecutionRepository, DiagramRepository, MetricsRepository interfaces - MetricsSnapshot record for agent metrics data - IngestionConfig for buffer-capacity/batch-size/flush-interval-ms properties - ClickHouseConfig exposing JdbcTemplate bean Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>