feat: Complete pipeline hot-rebuild implementation with acceptance tests

- Implements pipeline hot-rebuild with state preservation (issue #43)
- Adds auto-injection of MVP stages for missing capabilities
- Adds radial camera mode for polar coordinate scanning
- Adds afterimage and motionblur effects using framebuffer history
- Adds comprehensive acceptance tests for camera modes and pipeline rebuild
- Updates presets.toml with new effect configurations

Related to: #35 (Pipeline Mutation API epic)
Closes: #43, #44, #45

engine/pipeline/adapters/__init__.py

@@ -4,7 +4,7 @@ This module provides adapters that wrap existing components
 (EffectPlugin, Display, DataSource, Camera) as Stage implementations.
 """
 
-from .camera import CameraStage
+from .camera import CameraClockStage, CameraStage
 from .data_source import DataSourceStage, PassthroughStage, SourceItemsToBufferStage
 from .display import DisplayStage
 from .effect_plugin import EffectPluginStage
@@ -30,6 +30,7 @@ __all__ = [
     "PassthroughStage",
     "SourceItemsToBufferStage",
     "CameraStage",
+    "CameraClockStage",
     "ViewportFilterStage",
     "FontStage",
     "ImageToTextStage",