refactor: move timeline zoom to custom hook

apps/web/src/hooks/use-timeline-zoom.ts

@@ -0,0 +1,54 @@
+import { useState, useCallback, useEffect, RefObject } from "react";
+
+interface UseTimelineZoomProps {
+  containerRef: RefObject<HTMLDivElement>;
+  isInTimeline?: boolean;
+}
+
+interface UseTimelineZoomReturn {
+  zoomLevel: number;
+  setZoomLevel: (zoomLevel: number | ((prev: number) => number)) => void;
+  handleWheel: (e: React.WheelEvent) => void;
+}
+
+export function useTimelineZoom({
+  containerRef,
+  isInTimeline = false,
+}: UseTimelineZoomProps): UseTimelineZoomReturn {
+  const [zoomLevel, setZoomLevel] = useState(1);
+
+  const handleWheel = useCallback((e: React.WheelEvent) => {
+    // Only zoom if user is using pinch gesture (ctrlKey or metaKey is true)
+    if (e.ctrlKey || e.metaKey) {
+      e.preventDefault();
+      const delta = e.deltaY > 0 ? -0.05 : 0.05;
+      setZoomLevel((prev) => Math.max(0.1, Math.min(10, prev + delta)));
+    }
+    // Otherwise, allow normal scrolling
+  }, []);
+
+  // Prevent browser zooming in/out when in timeline
+  useEffect(() => {
+    const preventZoom = (e: WheelEvent) => {
+      if (
+        isInTimeline &&
+        (e.ctrlKey || e.metaKey) &&
+        containerRef.current?.contains(e.target as Node)
+      ) {
+        e.preventDefault();
+      }
+    };
+
+    document.addEventListener("wheel", preventZoom, { passive: false });
+
+    return () => {
+      document.removeEventListener("wheel", preventZoom);
+    };
+  }, [isInTimeline, containerRef]);
+
+  return {
+    zoomLevel,
+    setZoomLevel,
+    handleWheel,
+  };
+}