//! Layer 6: Adapters
//!
//! This layer provides user-facing APIs that adapt the engine layer for different
//! execution modes and use cases:
//!
//! - **Batch**: Unified adapter for sequential execution
//! - **Streaming**: Chunked processing for large datasets
//! - **Online**: Incremental updates for real-time data
// Unified batch adapter for LOWESS smoothing.
// Streaming LOWESS for large datasets.
// Online LOWESS for real-time data streams.