feat(integration): Complete feature rewrite with pipeline architecture, effects system, and display improvements

Major changes:
- Pipeline architecture with capability-based dependency resolution
- Effects plugin system with performance monitoring
- Display abstraction with multiple backends (terminal, null, websocket)
- Camera system for viewport scrolling
- Sensor framework for real-time input
- Command-and-control system via ntfy
- WebSocket display backend for browser clients
- Comprehensive test suite and documentation

Issue #48: ADR for preset scripting language included

This commit consolidates 110 individual commits into a single
feature integration that can be reviewed and tested before
further refinement.

engine/data_sources/__init__.py

@@ -0,0 +1,12 @@
+"""
+Data source implementations for the pipeline architecture.
+
+Import directly from submodules:
+    from engine.data_sources.sources import DataSource, SourceItem, HeadlinesDataSource
+    from engine.data_sources.pipeline_introspection import PipelineIntrospectionSource
+"""
+
+# Re-export for convenience
+from engine.data_sources.sources import ImageItem, SourceItem
+
+__all__ = ["ImageItem", "SourceItem"]