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/presets.py

@@ -50,6 +50,11 @@ class PipelinePreset:
     border: bool | BorderMode = (
         False  # Border mode: False=off, True=simple, BorderMode.UI for panel
     )
+    # Extended fields for fine-tuning
+    camera_speed: float = 1.0  # Camera movement speed
+    viewport_width: int = 80  # Viewport width in columns
+    viewport_height: int = 24  # Viewport height in rows
+    source_items: list[dict[str, Any]] | None = None  # For ListDataSource
 
     def to_params(self) -> PipelineParams:
         """Convert to PipelineParams."""
@@ -67,6 +72,8 @@ class PipelinePreset:
         )
         params.camera_mode = self.camera
         params.effect_order = self.effects.copy()
+        # Note: camera_speed, viewport_width/height are not stored in PipelineParams
+        # They are used directly from the preset object in pipeline_runner.py
         return params
 
     @classmethod
@@ -80,6 +87,10 @@ class PipelinePreset:
             camera=data.get("camera", "vertical"),
             effects=data.get("effects", []),
             border=data.get("border", False),
+            camera_speed=data.get("camera_speed", 1.0),
+            viewport_width=data.get("viewport_width", 80),
+            viewport_height=data.get("viewport_height", 24),
+            source_items=data.get("source_items"),
         )