feat(pipeline): add unified pipeline architecture with Stage abstraction

- Add engine/pipeline/ module with Stage ABC, PipelineContext, PipelineParams
- Stage provides unified interface for sources, effects, displays, cameras
- Pipeline class handles DAG-based execution with dependency resolution
- PipelinePreset for pre-configured pipelines (demo, poetry, pipeline, etc.)
- Add PipelineParams as params layer for animation-driven config
- Add StageRegistry for unified stage registration
- Add sources_v2.py with DataSource.is_dynamic property
- Add animation.py with Preset and AnimationController
- Skip ntfy integration tests by default (require -m integration)
- Skip e2e tests by default (require -m e2e)
- Update pipeline.py with comprehensive introspection methods

mise.toml

@@ -42,6 +42,13 @@ run-demo = { run = "uv run mainline.py --demo --display pygame", depends = ["syn
 run-pipeline = "uv run mainline.py --pipeline-diagram"
 run-pipeline-demo = { run = "uv run mainline.py --pipeline-demo --display pygame", depends = ["sync-all"] }
 
+# =====================
+# Presets (Animation-controlled modes)
+# =====================
+
+run-preset-demo = { run = "uv run mainline.py --preset demo --display pygame", depends = ["sync-all"] }
+run-preset-pipeline = { run = "uv run mainline.py --preset pipeline --display pygame", depends = ["sync-all"] }
+
 # =====================
 # Command & Control
 # =====================