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

engine/pipeline/presets.py

@@ -0,0 +1,155 @@
+"""
+Pipeline presets - Pre-configured pipeline configurations.
+
+Provides PipelinePreset as a unified preset system that wraps
+the existing Preset class from animation.py for backwards compatibility.
+"""
+
+from dataclasses import dataclass, field
+
+from engine.animation import Preset as AnimationPreset
+from engine.pipeline.params import PipelineParams
+
+
+@dataclass
+class PipelinePreset:
+    """Pre-configured pipeline with stages and animation.
+
+    A PipelinePreset packages:
+    - Initial params: Starting configuration
+    - Stages: List of stage configurations to create
+    - Animation: Optional animation controller
+
+    This is the new unified preset that works with the Pipeline class.
+    """
+
+    name: str
+    description: str = ""
+    source: str = "headlines"
+    display: str = "terminal"
+    camera: str = "vertical"
+    effects: list[str] = field(default_factory=list)
+    initial_params: PipelineParams | None = None
+    animation_preset: AnimationPreset | None = None
+
+    def to_params(self) -> PipelineParams:
+        """Convert to PipelineParams."""
+        if self.initial_params:
+            return self.initial_params.copy()
+        params = PipelineParams()
+        params.source = self.source
+        params.display = self.display
+        params.camera_mode = self.camera
+        params.effect_order = self.effects.copy()
+        return params
+
+    @classmethod
+    def from_animation_preset(cls, preset: AnimationPreset) -> "PipelinePreset":
+        """Create a PipelinePreset from an existing animation Preset."""
+        params = preset.initial_params
+        return cls(
+            name=preset.name,
+            description=preset.description,
+            source=params.source,
+            display=params.display,
+            camera=params.camera_mode,
+            effects=params.effect_order.copy(),
+            initial_params=params,
+            animation_preset=preset,
+        )
+
+    def create_animation_controller(self):
+        """Create an AnimationController from this preset."""
+        if self.animation_preset:
+            return self.animation_preset.create_controller()
+        return None
+
+
+# Built-in presets
+DEMO_PRESET = PipelinePreset(
+    name="demo",
+    description="Demo mode with effect cycling and camera modes",
+    source="headlines",
+    display="terminal",
+    camera="vertical",
+    effects=["noise", "fade", "glitch", "firehose", "hud"],
+)
+
+POETRY_PRESET = PipelinePreset(
+    name="poetry",
+    description="Poetry feed with subtle effects",
+    source="poetry",
+    display="terminal",
+    camera="vertical",
+    effects=["fade", "hud"],
+)
+
+PIPELINE_VIZ_PRESET = PipelinePreset(
+    name="pipeline",
+    description="Pipeline visualization mode",
+    source="pipeline",
+    display="terminal",
+    camera="trace",
+    effects=["hud"],
+)
+
+WEBSOCKET_PRESET = PipelinePreset(
+    name="websocket",
+    description="WebSocket display mode",
+    source="headlines",
+    display="websocket",
+    camera="vertical",
+    effects=["noise", "fade", "glitch", "hud"],
+)
+
+SIXEL_PRESET = PipelinePreset(
+    name="sixel",
+    description="Sixel graphics display mode",
+    source="headlines",
+    display="sixel",
+    camera="vertical",
+    effects=["noise", "fade", "glitch", "hud"],
+)
+
+FIREHOSE_PRESET = PipelinePreset(
+    name="firehose",
+    description="High-speed firehose mode",
+    source="headlines",
+    display="terminal",
+    camera="vertical",
+    effects=["noise", "fade", "glitch", "firehose", "hud"],
+)
+
+
+PRESETS: dict[str, PipelinePreset] = {
+    "demo": DEMO_PRESET,
+    "poetry": POETRY_PRESET,
+    "pipeline": PIPELINE_VIZ_PRESET,
+    "websocket": WEBSOCKET_PRESET,
+    "sixel": SIXEL_PRESET,
+    "firehose": FIREHOSE_PRESET,
+}
+
+
+def get_preset(name: str) -> PipelinePreset | None:
+    """Get a preset by name."""
+    return PRESETS.get(name)
+
+
+def list_presets() -> list[str]:
+    """List all available preset names."""
+    return list(PRESETS.keys())
+
+
+def create_preset_from_params(
+    params: PipelineParams, name: str = "custom"
+) -> PipelinePreset:
+    """Create a preset from PipelineParams."""
+    return PipelinePreset(
+        name=name,
+        source=params.source,
+        display=params.display,
+        camera=params.camera_mode,
+        effects=params.effect_order.copy(),
+        initial_params=params,
+    )