feat(figment): complete pipeline integration with native effect plugin

- Add engine/effects/plugins/figment.py (native pipeline implementation)
- Add engine/figment_render.py, engine/figment_trigger.py, engine/themes.py
- Add 3 SVG assets in figments/ (Mexican/Aztec motif)
- Add engine/display/backends/animation_report.py for debugging
- Add engine/pipeline/adapters/frame_capture.py for frame capture
- Add test-figment preset to presets.toml
- Add cairosvg optional dependency to pyproject.toml
- Update EffectPluginStage to support is_overlay attribute (for overlay effects)
- Add comprehensive tests: test_figment_effect.py, test_figment_pipeline.py, test_figment_render.py
- Remove obsolete test_ui_simple.py
- Update TODO.md with test cleanup plan
- Refactor test_adapters.py to use real components instead of mocks

This completes the figment SVG overlay feature integration using the modern pipeline architecture, avoiding legacy effects_plugins. All tests pass (758 total).

engine/pipeline/adapters/frame_capture.py

@@ -0,0 +1,165 @@
+"""
+Frame Capture Stage Adapter
+
+Wraps pipeline stages to capture frames for animation report generation.
+"""
+
+from typing import Any
+
+from engine.display.backends.animation_report import AnimationReportDisplay
+from engine.pipeline.core import PipelineContext, Stage
+
+
+class FrameCaptureStage(Stage):
+    """
+    Wrapper stage that captures frames before and after a wrapped stage.
+
+    This allows generating animation reports showing how each stage
+    transforms the data.
+    """
+
+    def __init__(
+        self,
+        wrapped_stage: Stage,
+        display: AnimationReportDisplay,
+        name: str | None = None,
+    ):
+        """
+        Initialize frame capture stage.
+
+        Args:
+            wrapped_stage: The stage to wrap and capture frames from
+            display: The animation report display to send frames to
+            name: Optional name for this capture stage
+        """
+        self._wrapped_stage = wrapped_stage
+        self._display = display
+        self.name = name or f"capture_{wrapped_stage.name}"
+        self.category = wrapped_stage.category
+        self.optional = wrapped_stage.optional
+
+        # Capture state
+        self._captured_input = False
+        self._captured_output = False
+
+    @property
+    def stage_type(self) -> str:
+        return self._wrapped_stage.stage_type
+
+    @property
+    def capabilities(self) -> set[str]:
+        return self._wrapped_stage.capabilities
+
+    @property
+    def dependencies(self) -> set[str]:
+        return self._wrapped_stage.dependencies
+
+    @property
+    def inlet_types(self) -> set:
+        return self._wrapped_stage.inlet_types
+
+    @property
+    def outlet_types(self) -> set:
+        return self._wrapped_stage.outlet_types
+
+    def init(self, ctx: PipelineContext) -> bool:
+        """Initialize the wrapped stage."""
+        return self._wrapped_stage.init(ctx)
+
+    def process(self, data: Any, ctx: PipelineContext) -> Any:
+        """
+        Process data through wrapped stage and capture frames.
+
+        Args:
+            data: Input data (typically a text buffer)
+            ctx: Pipeline context
+
+        Returns:
+            Output data from wrapped stage
+        """
+        # Capture input frame (before stage processing)
+        if isinstance(data, list) and all(isinstance(line, str) for line in data):
+            self._display.start_stage(f"{self._wrapped_stage.name}_input")
+            self._display.show(data)
+            self._captured_input = True
+
+        # Process through wrapped stage
+        result = self._wrapped_stage.process(data, ctx)
+
+        # Capture output frame (after stage processing)
+        if isinstance(result, list) and all(isinstance(line, str) for line in result):
+            self._display.start_stage(f"{self._wrapped_stage.name}_output")
+            self._display.show(result)
+            self._captured_output = True
+
+        return result
+
+    def cleanup(self) -> None:
+        """Cleanup the wrapped stage."""
+        self._wrapped_stage.cleanup()
+
+
+class FrameCaptureController:
+    """
+    Controller for managing frame capture across the pipeline.
+
+    This class provides an easy way to enable frame capture for
+    specific stages or the entire pipeline.
+    """
+
+    def __init__(self, display: AnimationReportDisplay):
+        """
+        Initialize frame capture controller.
+
+        Args:
+            display: The animation report display to use for capture
+        """
+        self._display = display
+        self._captured_stages: list[FrameCaptureStage] = []
+
+    def wrap_stage(self, stage: Stage, name: str | None = None) -> FrameCaptureStage:
+        """
+        Wrap a stage with frame capture.
+
+        Args:
+            stage: The stage to wrap
+            name: Optional name for the capture stage
+
+        Returns:
+            Wrapped stage that captures frames
+        """
+        capture_stage = FrameCaptureStage(stage, self._display, name)
+        self._captured_stages.append(capture_stage)
+        return capture_stage
+
+    def wrap_stages(self, stages: dict[str, Stage]) -> dict[str, Stage]:
+        """
+        Wrap multiple stages with frame capture.
+
+        Args:
+            stages: Dictionary of stage names to stages
+
+        Returns:
+            Dictionary of stage names to wrapped stages
+        """
+        wrapped = {}
+        for name, stage in stages.items():
+            wrapped[name] = self.wrap_stage(stage, name)
+        return wrapped
+
+    def get_captured_stages(self) -> list[FrameCaptureStage]:
+        """Get list of all captured stages."""
+        return self._captured_stages
+
+    def generate_report(self, title: str = "Pipeline Animation Report") -> str:
+        """
+        Generate the animation report.
+
+        Args:
+            title: Title for the report
+
+        Returns:
+            Path to the generated HTML file
+        """
+        report_path = self._display.generate_report(title)
+        return str(report_path)