refactor: centralize editor interaction state

Move timeline and preview gestures into dedicated controllers so hooks stay thin around editor state and DOM events.

This also routes drag and playback synchronization through manager APIs and reuses persistent wasm surfaces so scrubbing, seeking, and preview rendering stay in sync.

Made-with: Cursor

1 files changed, 7 insertions, 5 deletions

diff --git a/apps/web/src/core/managers/timeline-manager.ts b/apps/web/src/core/managers/timeline-manager.ts
index dbc3332b..6f54c5aa 100644
--- a/apps/web/src/core/managers/timeline-manager.ts
+++ b/apps/web/src/core/managers/timeline-manager.ts
@@ -9,6 +9,7 @@ import type {
 	RetimeConfig,
 } from "@/timeline";
 import { calculateTotalDuration } from "@/timeline";
+import { TimelineDragSource } from "@/timeline/drag-source";
 import { findTrackInSceneTracks } from "@/timeline/track-element-update";
 import {
 	canElementBeHidden,
@@ -67,6 +68,7 @@ export class TimelineManager {
 	private listeners = new Set<() => void>();
 	private previewOverlay = new Map<string, Partial<TimelineElement>>();
 	private previewTracks: SceneTracks | null = null;
+	public readonly dragSource = new TimelineDragSource();
 
 	constructor(private editor: EditorCore) {}
 
@@ -706,11 +708,11 @@ export class TimelineManager {
 	previewElements({
 		updates,
 	}: {
-		updates: Array<{
-			trackId: string;
-			elementId: string;
-			updates: Partial<TimelineElement>;
-		}>;
+		updates: readonly {
+			readonly trackId: string;
+			readonly elementId: string;
+			readonly updates: Partial<TimelineElement>;
+		}[];
 	}): void {
 		let changedOverlayCount = 0;
 		for (const { elementId, updates: elementUpdates } of updates) {