revert(zoom): drop selected-zoom preview override, preview the current frame

The a686fa0 override replaced findDominantRegion's resolved region with the
raw stored region (forcing strength=1 / transition=null). findDominantRegion
already resolves focus via getResolvedFocus — for focusMode:"auto" it
interpolates the cursor-followed focus from telemetry and applies clamp/blend/
transition. The override bypassed all of that, so previewing an auto-focus
zoom showed a stale static focus and an instant un-eased zoom that did not
match real playback/export.

Hold-to-preview now shows the natural zoom for the current playhead frame
(true before/after compare). The isPreviewingZoom flag is kept — it only
disables the un-zoomed editing guard so findDominantRegion's result is shown.
Previewing while the playhead is outside any zoom shows no zoom by design.

src/components/video-editor/VideoPlayback.tsx

@@ -59,8 +59,6 @@ import {
 	DEFAULT_CURSOR_SIZE,
 	DEFAULT_CURSOR_SMOOTHING,
 	DEFAULT_ROTATION_3D,
-	getRotation3D,
-	getZoomScale,
 	isRotation3DIdentity,
 	lerpRotation3D,
 	rotation3DPerspective,
@@ -1303,7 +1301,7 @@ const VideoPlayback = forwardRef<VideoPlaybackRef, VideoPlaybackProps>(
 			let lastTransformIsIdentity = true;
 			let lastPerspectiveValue = 0;
 			const ticker = () => {
-				let { region, strength, blendedScale, rotation3D, transition } = findDominantRegion(
+				const { region, strength, blendedScale, rotation3D, transition } = findDominantRegion(
 					zoomRegionsRef.current,
 					currentTimeRef.current,
 					{
@@ -1312,21 +1310,6 @@ const VideoPlayback = forwardRef<VideoPlaybackRef, VideoPlaybackProps>(
 					},
 				);
 
-				// While holding Preview, show the SELECTED zoom (what the settings panel
-				// is editing) at full strength, independent of the playhead — otherwise
-				// the preview reflects whatever region sits at currentTime, which may be
-				// none or a different zoom when the playhead isn't inside the selection.
-				if (isPreviewingZoomRef.current && selectedZoomIdRef.current) {
-					const sel = zoomRegionsRef.current.find((r) => r.id === selectedZoomIdRef.current);
-					if (sel) {
-						region = sel;
-						strength = 1;
-						blendedScale = getZoomScale(sel);
-						rotation3D = getRotation3D(sel);
-						transition = null;
-					}
-				}
-
 				const defaultFocus = DEFAULT_FOCUS;
 				let targetScaleFactor = 1;
 				let targetFocus = defaultFocus;