feat: add pipeline introspection demo mode

- Add PipelineIntrospectionSource that renders live ASCII DAG with metrics
- Add PipelineMetricsSensor exposing pipeline performance as sensor values
- Add PipelineIntrospectionDemo controller with 3-phase animation:
  - Phase 1: Toggle effects one at a time (3s each)
  - Phase 2: LFO drives intensity default→max→min→default
  - Phase 3: All effects with shared LFO (infinite loop)
- Add pipeline-inspect preset
- Add get_frame_times() to Pipeline for sparkline data
- Add tests for new components
- Update mise.toml with pipeline-inspect preset task

presets.toml

@@ -30,17 +30,6 @@ viewport_height = 24
 camera_speed = 0.5
 firehose_enabled = false
 
-[presets.pipeline]
-description = "Pipeline visualization mode"
-source = "pipeline"
-display = "terminal"
-camera = "trace"
-effects = ["hud"]
-viewport_width = 80
-viewport_height = 24
-camera_speed = 1.0
-firehose_enabled = false
-
 [presets.websocket]
 description = "WebSocket display mode"
 source = "headlines"
@@ -74,6 +63,17 @@ viewport_height = 24
 camera_speed = 2.0
 firehose_enabled = true
 
+[presets.pipeline-inspect]
+description = "Live pipeline introspection with DAG and performance metrics"
+source = "pipeline-inspect"
+display = "terminal"
+camera = "vertical"
+effects = ["hud"]
+viewport_width = 100
+viewport_height = 35
+camera_speed = 0.3
+firehose_enabled = false
+
 # Sensor configuration (for future use with param bindings)
 [sensors.mic]
 enabled = false