feat: Clip effects, asset sorting, and timeline improvements

Major features and improvements:

* **Clip Effects**:
  * Added UI in Properties Panel to manage effects on video/image clips (add, remove, toggle, reorder).
  * Implemented dynamic parameter fields for effects.
  * Added support for keyframing effect parameters.

* **Assets Panel**:
  * Added sorting options: Name, Type, Duration, and File Size.
  * Persisted view preferences (grid/list mode, sort order) to local storage.
  * Refactored media item rendering and drag interactions.

* **Timeline & Interaction**:
  * **Keyframe Dragging**: Added ability to drag keyframes directly on the timeline element.
  * **Resizing**: Improved resize logic to respect neighboring clips (prevents overlaps).
  * **Visuals**: Implemented tiled background rendering for video/image clips on the timeline.
  * **Shortcuts**: Added "Deselect All" action bound to the `Escape` key.
  * **Fixes**: Corrected drag-and-drop coordinate calculations when the timeline track area is scrolled.

* **Text Elements**:
  * Refactored text background storage to use an explicit `enabled` flag.
  * Added `V8toV9` storage migration to update existing projects.

* **Architecture**:
  * Moved export state management to `ProjectManager` for better lifecycle handling.
  * Refactored `PropertiesPanel` sections to be more composable (custom headers, borders).

11 files changed, 548 insertions, 16 deletions

diff --git a/apps/web/src/lib/commands/timeline/element/effects/add-effect.ts b/apps/web/src/lib/commands/timeline/element/effects/add-effect.ts
new file mode 100644
index 00000000..5299749d
--- /dev/null
+++ b/apps/web/src/lib/commands/timeline/element/effects/add-effect.ts
@@ -0,0 +1,74 @@
+import { Command } from "@/lib/commands/base-command";
+import { EditorCore } from "@/core";
+import { isVisualElement, updateElementInTracks } from "@/lib/timeline";
+import type { TimelineTrack, VisualElement } from "@/types/timeline";
+import { buildDefaultEffectInstance } from "@/lib/effects";
+
+function addEffectToElement({
+	element,
+	effectType,
+}: {
+	element: VisualElement;
+	effectType: string;
+}): VisualElement {
+	const instance = buildDefaultEffectInstance({ effectType });
+	const currentEffects = element.effects ?? [];
+	return { ...element, effects: [...currentEffects, instance] };
+}
+
+export class AddClipEffectCommand extends Command {
+	private savedState: TimelineTrack[] | null = null;
+	private effectId: string | null = null;
+	private readonly trackId: string;
+	private readonly elementId: string;
+	private readonly effectType: string;
+
+	constructor({
+		trackId,
+		elementId,
+		effectType,
+	}: {
+		trackId: string;
+		elementId: string;
+		effectType: string;
+	}) {
+		super();
+		this.trackId = trackId;
+		this.elementId = elementId;
+		this.effectType = effectType;
+	}
+
+	execute(): void {
+		const editor = EditorCore.getInstance();
+		this.savedState = editor.timeline.getTracks();
+
+		const updatedTracks = updateElementInTracks({
+			tracks: this.savedState,
+			trackId: this.trackId,
+			elementId: this.elementId,
+			elementPredicate: isVisualElement,
+		update: (element) => {
+			const updated = addEffectToElement({
+				element: element as VisualElement,
+				effectType: this.effectType,
+			});
+				const effects = updated.effects ?? [];
+				this.effectId = effects[effects.length - 1]?.id ?? null;
+				return updated;
+			},
+		});
+
+		editor.timeline.updateTracks(updatedTracks);
+	}
+
+	undo(): void {
+		if (this.savedState) {
+			const editor = EditorCore.getInstance();
+			editor.timeline.updateTracks(this.savedState);
+		}
+	}
+
+	getEffectId(): string | null {
+		return this.effectId;
+	}
+}
diff --git a/apps/web/src/lib/commands/timeline/element/effects/index.ts b/apps/web/src/lib/commands/timeline/element/effects/index.ts
new file mode 100644
index 00000000..133ce661
--- /dev/null
+++ b/apps/web/src/lib/commands/timeline/element/effects/index.ts
@@ -0,0 +1,5 @@
+export { AddClipEffectCommand } from "./add-effect";
+export { RemoveClipEffectCommand } from "./remove-effect";
+export { ToggleClipEffectCommand } from "./toggle-effect";
+export { UpdateClipEffectParamsCommand } from "./update-effect-params";
+export { ReorderClipEffectsCommand } from "./reorder-effect";
diff --git a/apps/web/src/lib/commands/timeline/element/effects/remove-effect.ts b/apps/web/src/lib/commands/timeline/element/effects/remove-effect.ts
new file mode 100644
index 00000000..b475474f
--- /dev/null
+++ b/apps/web/src/lib/commands/timeline/element/effects/remove-effect.ts
@@ -0,0 +1,65 @@
+import { Command } from "@/lib/commands/base-command";
+import { EditorCore } from "@/core";
+import { isVisualElement, updateElementInTracks } from "@/lib/timeline";
+import type { TimelineTrack, VisualElement } from "@/types/timeline";
+
+function removeEffectFromElement({
+	element,
+	effectId,
+}: {
+	element: VisualElement;
+	effectId: string;
+}): VisualElement {
+	const currentEffects = element.effects ?? [];
+	const filtered = currentEffects.filter((effect) => effect.id !== effectId);
+	return { ...element, effects: filtered };
+}
+
+export class RemoveClipEffectCommand extends Command {
+	private savedState: TimelineTrack[] | null = null;
+	private readonly trackId: string;
+	private readonly elementId: string;
+	private readonly effectId: string;
+
+	constructor({
+		trackId,
+		elementId,
+		effectId,
+	}: {
+		trackId: string;
+		elementId: string;
+		effectId: string;
+	}) {
+		super();
+		this.trackId = trackId;
+		this.elementId = elementId;
+		this.effectId = effectId;
+	}
+
+	execute(): void {
+		const editor = EditorCore.getInstance();
+		this.savedState = editor.timeline.getTracks();
+
+		const updatedTracks = updateElementInTracks({
+			tracks: this.savedState,
+			trackId: this.trackId,
+			elementId: this.elementId,
+			elementPredicate: isVisualElement,
+		update: (element) => {
+			return removeEffectFromElement({
+				element: element as VisualElement,
+				effectId: this.effectId,
+			});
+			},
+		});
+
+		editor.timeline.updateTracks(updatedTracks);
+	}
+
+	undo(): void {
+		if (this.savedState) {
+			const editor = EditorCore.getInstance();
+			editor.timeline.updateTracks(this.savedState);
+		}
+	}
+}
diff --git a/apps/web/src/lib/commands/timeline/element/effects/reorder-effect.ts b/apps/web/src/lib/commands/timeline/element/effects/reorder-effect.ts
new file mode 100644
index 00000000..81c66503
--- /dev/null
+++ b/apps/web/src/lib/commands/timeline/element/effects/reorder-effect.ts
@@ -0,0 +1,73 @@
+import { Command } from "@/lib/commands/base-command";
+import { EditorCore } from "@/core";
+import { isVisualElement, updateElementInTracks } from "@/lib/timeline";
+import type { TimelineTrack, VisualElement } from "@/types/timeline";
+
+function reorderEffectsOnElement({
+	element,
+	fromIndex,
+	toIndex,
+}: {
+	element: VisualElement;
+	fromIndex: number;
+	toIndex: number;
+}): VisualElement {
+	const effects = [...(element.effects ?? [])];
+	const [moved] = effects.splice(fromIndex, 1);
+	effects.splice(toIndex, 0, moved);
+	return { ...element, effects };
+}
+
+export class ReorderClipEffectsCommand extends Command {
+	private savedState: TimelineTrack[] | null = null;
+	private readonly trackId: string;
+	private readonly elementId: string;
+	private readonly fromIndex: number;
+	private readonly toIndex: number;
+
+	constructor({
+		trackId,
+		elementId,
+		fromIndex,
+		toIndex,
+	}: {
+		trackId: string;
+		elementId: string;
+		fromIndex: number;
+		toIndex: number;
+	}) {
+		super();
+		this.trackId = trackId;
+		this.elementId = elementId;
+		this.fromIndex = fromIndex;
+		this.toIndex = toIndex;
+	}
+
+	execute(): void {
+		const editor = EditorCore.getInstance();
+		this.savedState = editor.timeline.getTracks();
+
+		const updatedTracks = updateElementInTracks({
+			tracks: this.savedState,
+			trackId: this.trackId,
+			elementId: this.elementId,
+			elementPredicate: isVisualElement,
+		update: (element) => {
+			return reorderEffectsOnElement({
+				element: element as VisualElement,
+				fromIndex: this.fromIndex,
+				toIndex: this.toIndex,
+			});
+			},
+		});
+
+		editor.timeline.updateTracks(updatedTracks);
+	}
+
+	undo(): void {
+		if (this.savedState) {
+			const editor = EditorCore.getInstance();
+			editor.timeline.updateTracks(this.savedState);
+		}
+	}
+}
diff --git a/apps/web/src/lib/commands/timeline/element/effects/toggle-effect.ts b/apps/web/src/lib/commands/timeline/element/effects/toggle-effect.ts
new file mode 100644
index 00000000..70bf955d
--- /dev/null
+++ b/apps/web/src/lib/commands/timeline/element/effects/toggle-effect.ts
@@ -0,0 +1,67 @@
+import { Command } from "@/lib/commands/base-command";
+import { EditorCore } from "@/core";
+import { isVisualElement, updateElementInTracks } from "@/lib/timeline";
+import type { TimelineTrack, VisualElement } from "@/types/timeline";
+
+export function toggleEffectOnElement({
+	element,
+	effectId,
+}: {
+	element: VisualElement;
+	effectId: string;
+}): VisualElement {
+	const currentEffects = element.effects ?? [];
+	const updated = currentEffects.map((effect) =>
+		effect.id === effectId ? { ...effect, enabled: !effect.enabled } : effect,
+	);
+	return { ...element, effects: updated };
+}
+
+export class ToggleClipEffectCommand extends Command {
+	private savedState: TimelineTrack[] | null = null;
+	private readonly trackId: string;
+	private readonly elementId: string;
+	private readonly effectId: string;
+
+	constructor({
+		trackId,
+		elementId,
+		effectId,
+	}: {
+		trackId: string;
+		elementId: string;
+		effectId: string;
+	}) {
+		super();
+		this.trackId = trackId;
+		this.elementId = elementId;
+		this.effectId = effectId;
+	}
+
+	execute(): void {
+		const editor = EditorCore.getInstance();
+		this.savedState = editor.timeline.getTracks();
+
+		const updatedTracks = updateElementInTracks({
+			tracks: this.savedState,
+			trackId: this.trackId,
+			elementId: this.elementId,
+			elementPredicate: isVisualElement,
+		update: (element) => {
+			return toggleEffectOnElement({
+				element: element as VisualElement,
+				effectId: this.effectId,
+			});
+			},
+		});
+
+		editor.timeline.updateTracks(updatedTracks);
+	}
+
+	undo(): void {
+		if (this.savedState) {
+			const editor = EditorCore.getInstance();
+			editor.timeline.updateTracks(this.savedState);
+		}
+	}
+}
diff --git a/apps/web/src/lib/commands/timeline/element/effects/update-effect-params.ts b/apps/web/src/lib/commands/timeline/element/effects/update-effect-params.ts
new file mode 100644
index 00000000..d9bf0aad
--- /dev/null
+++ b/apps/web/src/lib/commands/timeline/element/effects/update-effect-params.ts
@@ -0,0 +1,86 @@
+import { Command } from "@/lib/commands/base-command";
+import { EditorCore } from "@/core";
+import { isVisualElement, updateElementInTracks } from "@/lib/timeline";
+import type { EffectParamValues } from "@/types/effects";
+import type { TimelineTrack, VisualElement } from "@/types/timeline";
+
+function updateEffectParamsOnElement({
+	element,
+	effectId,
+	params,
+}: {
+	element: VisualElement;
+	effectId: string;
+	params: Partial<EffectParamValues>;
+}): VisualElement {
+	const currentEffects = element.effects ?? [];
+	const updated = currentEffects.map((effect) => {
+		if (effect.id !== effectId) {
+			return effect;
+		}
+
+		const nextParams = { ...effect.params };
+		for (const [key, value] of Object.entries(params)) {
+			if (value !== undefined) {
+				nextParams[key] = value;
+			}
+		}
+
+		return { ...effect, params: nextParams };
+	});
+	return { ...element, effects: updated };
+}
+
+export class UpdateClipEffectParamsCommand extends Command {
+	private savedState: TimelineTrack[] | null = null;
+	private readonly trackId: string;
+	private readonly elementId: string;
+	private readonly effectId: string;
+	private readonly params: Partial<EffectParamValues>;
+
+	constructor({
+		trackId,
+		elementId,
+		effectId,
+		params,
+	}: {
+		trackId: string;
+		elementId: string;
+		effectId: string;
+		params: Partial<EffectParamValues>;
+	}) {
+		super();
+		this.trackId = trackId;
+		this.elementId = elementId;
+		this.effectId = effectId;
+		this.params = params;
+	}
+
+	execute(): void {
+		const editor = EditorCore.getInstance();
+		this.savedState = editor.timeline.getTracks();
+
+		const updatedTracks = updateElementInTracks({
+			tracks: this.savedState,
+			trackId: this.trackId,
+			elementId: this.elementId,
+			elementPredicate: isVisualElement,
+		update: (element) => {
+			return updateEffectParamsOnElement({
+				element: element as VisualElement,
+				effectId: this.effectId,
+				params: this.params,
+			});
+			},
+		});
+
+		editor.timeline.updateTracks(updatedTracks);
+	}
+
+	undo(): void {
+		if (this.savedState) {
+			const editor = EditorCore.getInstance();
+			editor.timeline.updateTracks(this.savedState);
+		}
+	}
+}
diff --git a/apps/web/src/lib/commands/timeline/element/index.ts b/apps/web/src/lib/commands/timeline/element/index.ts
index 69d94c24..413d1adf 100644
--- a/apps/web/src/lib/commands/timeline/element/index.ts
+++ b/apps/web/src/lib/commands/timeline/element/index.ts
@@ -10,3 +10,4 @@ export { ToggleElementsVisibilityCommand } from "./toggle-elements-visibility";
 export { ToggleElementsMutedCommand } from "./toggle-elements-muted";
 export { MoveElementCommand } from "./move-elements";
 export * from "./keyframes";
+export * from "./effects";
diff --git a/apps/web/src/lib/commands/timeline/element/keyframes/index.ts b/apps/web/src/lib/commands/timeline/element/keyframes/index.ts
index f221e33a..c03b14e9 100644
--- a/apps/web/src/lib/commands/timeline/element/keyframes/index.ts
+++ b/apps/web/src/lib/commands/timeline/element/keyframes/index.ts
@@ -1,3 +1,5 @@
+export * from "./remove-effect-param-keyframe";
 export * from "./remove-keyframe";
 export * from "./retime-keyframe";
+export * from "./upsert-effect-param-keyframe";
 export * from "./upsert-keyframe";
diff --git a/apps/web/src/lib/commands/timeline/element/keyframes/remove-effect-param-keyframe.ts b/apps/web/src/lib/commands/timeline/element/keyframes/remove-effect-param-keyframe.ts
new file mode 100644
index 00000000..d4922532
--- /dev/null
+++ b/apps/web/src/lib/commands/timeline/element/keyframes/remove-effect-param-keyframe.ts
@@ -0,0 +1,68 @@
+import { EditorCore } from "@/core";
+import { Command } from "@/lib/commands/base-command";
+import { removeEffectParamKeyframe } from "@/lib/animation/effect-param-channel";
+import { updateElementInTracks } from "@/lib/timeline";
+import { isVisualElement } from "@/lib/timeline/element-utils";
+import type { TimelineTrack } from "@/types/timeline";
+
+export class RemoveEffectParamKeyframeCommand extends Command {
+	private savedState: TimelineTrack[] | null = null;
+	private readonly trackId: string;
+	private readonly elementId: string;
+	private readonly effectId: string;
+	private readonly paramKey: string;
+	private readonly keyframeId: string;
+
+	constructor({
+		trackId,
+		elementId,
+		effectId,
+		paramKey,
+		keyframeId,
+	}: {
+		trackId: string;
+		elementId: string;
+		effectId: string;
+		paramKey: string;
+		keyframeId: string;
+	}) {
+		super();
+		this.trackId = trackId;
+		this.elementId = elementId;
+		this.effectId = effectId;
+		this.paramKey = paramKey;
+		this.keyframeId = keyframeId;
+	}
+
+	execute(): void {
+		const editor = EditorCore.getInstance();
+		this.savedState = editor.timeline.getTracks();
+
+		const updatedTracks = updateElementInTracks({
+			tracks: this.savedState,
+			trackId: this.trackId,
+			elementId: this.elementId,
+			elementPredicate: isVisualElement,
+			update: (element) => {
+				const animations = removeEffectParamKeyframe({
+					animations: element.animations,
+					effectId: this.effectId,
+					paramKey: this.paramKey,
+					keyframeId: this.keyframeId,
+				});
+				return { ...element, animations };
+			},
+		});
+
+		editor.timeline.updateTracks(updatedTracks);
+	}
+
+	undo(): void {
+		if (!this.savedState) {
+			return;
+		}
+
+		const editor = EditorCore.getInstance();
+		editor.timeline.updateTracks(this.savedState);
+	}
+}
diff --git a/apps/web/src/lib/commands/timeline/element/keyframes/upsert-effect-param-keyframe.ts b/apps/web/src/lib/commands/timeline/element/keyframes/upsert-effect-param-keyframe.ts
new file mode 100644
index 00000000..f5236279
--- /dev/null
+++ b/apps/web/src/lib/commands/timeline/element/keyframes/upsert-effect-param-keyframe.ts
@@ -0,0 +1,84 @@
+import { EditorCore } from "@/core";
+import { Command } from "@/lib/commands/base-command";
+import { upsertEffectParamKeyframe } from "@/lib/animation/effect-param-channel";
+import { updateElementInTracks } from "@/lib/timeline";
+import { isVisualElement } from "@/lib/timeline/element-utils";
+import type { TimelineTrack } from "@/types/timeline";
+
+export class UpsertEffectParamKeyframeCommand extends Command {
+	private savedState: TimelineTrack[] | null = null;
+	private readonly trackId: string;
+	private readonly elementId: string;
+	private readonly effectId: string;
+	private readonly paramKey: string;
+	private readonly time: number;
+	private readonly value: number;
+	private readonly interpolation: "linear" | "hold" | undefined;
+	private readonly keyframeId: string | undefined;
+
+	constructor({
+		trackId,
+		elementId,
+		effectId,
+		paramKey,
+		time,
+		value,
+		interpolation,
+		keyframeId,
+	}: {
+		trackId: string;
+		elementId: string;
+		effectId: string;
+		paramKey: string;
+		time: number;
+		value: number;
+		interpolation?: "linear" | "hold";
+		keyframeId?: string;
+	}) {
+		super();
+		this.trackId = trackId;
+		this.elementId = elementId;
+		this.effectId = effectId;
+		this.paramKey = paramKey;
+		this.time = time;
+		this.value = value;
+		this.interpolation = interpolation;
+		this.keyframeId = keyframeId;
+	}
+
+	execute(): void {
+		const editor = EditorCore.getInstance();
+		this.savedState = editor.timeline.getTracks();
+
+		const updatedTracks = updateElementInTracks({
+			tracks: this.savedState,
+			trackId: this.trackId,
+			elementId: this.elementId,
+			elementPredicate: isVisualElement,
+			update: (element) => {
+				const boundedTime = Math.max(0, Math.min(this.time, element.duration));
+				const animations = upsertEffectParamKeyframe({
+					animations: element.animations,
+					effectId: this.effectId,
+					paramKey: this.paramKey,
+					time: boundedTime,
+					value: this.value,
+					interpolation: this.interpolation,
+					keyframeId: this.keyframeId,
+				});
+				return { ...element, animations };
+			},
+		});
+
+		editor.timeline.updateTracks(updatedTracks);
+	}
+
+	undo(): void {
+		if (!this.savedState) {
+			return;
+		}
+
+		const editor = EditorCore.getInstance();
+		editor.timeline.updateTracks(this.savedState);
+	}
+}
diff --git a/apps/web/src/lib/commands/timeline/element/move-elements.ts b/apps/web/src/lib/commands/timeline/element/move-elements.ts
index 6aadcf16..51e18c21 100644
--- a/apps/web/src/lib/commands/timeline/element/move-elements.ts
+++ b/apps/web/src/lib/commands/timeline/element/move-elements.ts
@@ -11,6 +11,7 @@ import {
 	validateElementTrackCompatibility,
 	enforceMainTrackStart,
 } from "@/lib/timeline/track-utils";
+import { rippleShiftElements } from "@/lib/timeline/ripple-utils";
 
 export class MoveElementCommand extends Command {
 	private savedState: TimelineTrack[] | null = null;
@@ -19,6 +20,7 @@ export class MoveElementCommand extends Command {
 	private readonly elementId: string;
 	private readonly newStartTime: number;
 	private readonly createTrack: { type: TrackType; index: number } | undefined;
+	private readonly rippleEnabled: boolean;
 
 	constructor({
 		sourceTrackId,
@@ -26,12 +28,14 @@ export class MoveElementCommand extends Command {
 		elementId,
 		newStartTime,
 		createTrack,
+		rippleEnabled = false,
 	}: {
 		sourceTrackId: string;
 		targetTrackId: string;
 		elementId: string;
 		newStartTime: number;
 		createTrack?: { type: TrackType; index: number };
+		rippleEnabled?: boolean;
 	}) {
 		super();
 		this.sourceTrackId = sourceTrackId;
@@ -39,6 +43,7 @@ export class MoveElementCommand extends Command {
 		this.elementId = elementId;
 		this.newStartTime = newStartTime;
 		this.createTrack = createTrack;
+		this.rippleEnabled = rippleEnabled;
 	}
 
 	execute(): void {
@@ -53,8 +58,7 @@ export class MoveElementCommand extends Command {
 		);
 
 		if (!sourceTrack || !element) {
-			console.error("Source track or element not found");
-			return;
+			throw new Error("Source track or element not found");
 		}
 
 		let targetTrack = this.savedState.find((track) => track.id === this.targetTrackId);
@@ -69,8 +73,7 @@ export class MoveElementCommand extends Command {
 			targetTrack = newTrack;
 		}
 		if (!targetTrack) {
-			console.error("Target track not found");
-			return;
+			throw new Error("Target track not found");
 		}
 
 		const validation = validateElementTrackCompatibility({
@@ -79,8 +82,7 @@ export class MoveElementCommand extends Command {
 		});
 
 		if (!validation.isValid) {
-			console.error(validation.errorMessage);
-			return;
+			throw new Error(validation.errorMessage);
 		}
 
 		const adjustedStartTime = enforceMainTrackStart({
@@ -105,27 +107,32 @@ export class MoveElementCommand extends Command {
 					elements: track.elements.map((trackElement) =>
 						trackElement.id === this.elementId ? movedElement : trackElement,
 					),
-				};
+				} as typeof track;
 			}
 
 			if (track.id === this.sourceTrackId) {
-				return {
-					...track,
-					elements: track.elements.filter(
-						(trackElement) => trackElement.id !== this.elementId,
-					),
-				};
+				const remainingElements = track.elements.filter(
+					(trackElement) => trackElement.id !== this.elementId,
+				);
+				const shiftedElements = this.rippleEnabled
+					? rippleShiftElements({
+							elements: remainingElements,
+							afterTime: element.startTime,
+							shiftAmount: element.duration,
+						})
+					: remainingElements;
+				return { ...track, elements: shiftedElements } as typeof track;
 			}
 
 			if (track.id === this.targetTrackId) {
 				return {
 					...track,
 					elements: [...track.elements, movedElement],
-				};
+				} as typeof track;
 			}
 
-		return track;
-	});
+			return track;
+		});
 
 		if (!isSameTrack) {
 			const sourceTrackAfterMove = updatedTracks.find(