feat: introduce WebGL effects system and Blur effect

This implements the foundational architecture for video effects, starting with a multi-pass WebGL rendering pipeline and a customizable Gaussian Blur effect.

Key changes:
- WebGL Engine: Added `raw-loader` for `.glsl` shaders, multi-pass framebuffer rendering, and live offscreen canvas previews.
- Node Architecture: Replaced hardcoded background blur with `CompositeEffectNode` and added `EffectLayerNode` to apply effects to specific visual elements.
- Timeline & DND: Added a new `effect` track type. Upgraded drag-and-drop to support dropping effects directly onto the timeline. Consolidated track constants into a cleaner `TRACK_CONFIG`.
- UI/UX: Added an Effects tab in the assets panel with live previews. Added an Effect Properties panel with sliders and inputs for fine-tuning parameters.
- Data Model: Added `sourceDuration` to video and audio elements, and wrote a v8 storage migration to update existing projects to the new schema.
- Docs: Added `CHANGELOG.md` tracking v0.1.0 and v0.2.0, plus `docs/effects-renderer.md` to document the new WebGL pipeline.

1 files changed, 3 insertions, 0 deletions

diff --git a/apps/web/src/components/editor/panels/timeline/timeline-track.tsx b/apps/web/src/components/editor/panels/timeline/timeline-track.tsx
index 42faadaf..fbc7cb3f 100644
--- a/apps/web/src/components/editor/panels/timeline/timeline-track.tsx
+++ b/apps/web/src/components/editor/panels/timeline/timeline-track.tsx
@@ -32,6 +32,7 @@ interface TimelineTrackContentProps {
 	onTrackMouseDown?: (event: React.MouseEvent) => void;
 	onTrackClick?: (event: React.MouseEvent) => void;
 	shouldIgnoreClick?: () => boolean;
+	targetElementId?: string | null;
 }
 
 export function TimelineTrackContent({
@@ -48,6 +49,7 @@ export function TimelineTrackContent({
 	onTrackMouseDown,
 	onTrackClick,
 	shouldIgnoreClick,
+	targetElementId = null,
 }: TimelineTrackContentProps) {
 	const editor = useEditor();
 	const { isElementSelected, clearElementSelection } = useElementSelection();
@@ -102,6 +104,7 @@ export function TimelineTrackContent({
 									onElementClick({ event, element, track })
 								}
 								dragState={dragState}
+								isDropTarget={element.id === targetElementId}
 							/>
 						);
 					})