chore(pipeline): improve pipeline architecture

- Add capability-based dependency resolution with prefix matching
- Add EffectPluginStage with sensor binding support
- Add CameraStage adapter for camera integration
- Add DisplayStage adapter for display integration
- Add Pipeline metrics collection
- Add deprecation notices to legacy modules
- Update app.py with pipeline integration

engine/pipeline/adapters.py

@@ -56,7 +56,7 @@ class RenderStage(Stage):
 
     @property
     def dependencies(self) -> set[str]:
-        return {"source.items"}
+        return {"source"}
 
     def init(self, ctx: PipelineContext) -> bool:
         random.shuffle(self._pool)
@@ -142,7 +142,7 @@ class EffectPluginStage(Stage):
         """Process data through the effect."""
         if data is None:
             return None
-        from engine.effects import EffectContext
+        from engine.effects.types import EffectContext, apply_param_bindings
 
         w = ctx.params.viewport_width if ctx.params else 80
         h = ctx.params.viewport_height if ctx.params else 24
@@ -160,6 +160,17 @@ class EffectPluginStage(Stage):
             has_message=False,
             items=ctx.get("items", []),
         )
+
+        # Copy sensor state from PipelineContext to EffectContext
+        for key, value in ctx.state.items():
+            if key.startswith("sensor."):
+                effect_ctx.set_state(key, value)
+
+        # Apply sensor param bindings if effect has them
+        if hasattr(self._effect, "param_bindings") and self._effect.param_bindings:
+            bound_config = apply_param_bindings(self._effect, effect_ctx)
+            self._effect.configure(bound_config)
+
         return self._effect.process(data, effect_ctx)
 
 
@@ -221,9 +232,21 @@ class DataSourceStage(Stage):
 
 
 class ItemsStage(Stage):
-    """Stage that holds pre-fetched items and provides them to the pipeline."""
+    """Stage that holds pre-fetched items and provides them to the pipeline.
+
+    .. deprecated::
+        Use DataSourceStage with a proper DataSource instead.
+        ItemsStage is a legacy bootstrap mechanism.
+    """
 
     def __init__(self, items, name: str = "headlines"):
+        import warnings
+
+        warnings.warn(
+            "ItemsStage is deprecated. Use DataSourceStage with a DataSource instead.",
+            DeprecationWarning,
+            stacklevel=2,
+        )
         self._items = items
         self.name = name
         self.category = "source"