[4.6.0] Late animated props such as contentOffset are synced into style

Description

[!NOTE] This issue was authored by AI on behalf of @qq382724935.

_syncStylePropsBackToReact classifies native props using animatedProp.initial.value. A prop absent on the first evaluation is later written into settledStyle instead of settledProps.

Reproduction

const y = useSharedValue(-1);
const animatedProps = useAnimatedProps(() =>
  y.value < 0 ? {} : { contentOffset: { x: 0, y: y.value } }
);
// Attach animatedProps to an Animated.ScrollView with scrollable content.
// After mount:
y.value = withTiming(200);

Executing the unmodified sync method with initial {} and settled {contentOffset: {x: 0, y: 200}} produces:

{ settledProps: {}, settledStyle: { contentOffset: { x: 0, y: 200 } } }

Expected: contentOffset stays a native prop; its first appearance must not turn it into a style.

Environment: Reanimated 4.6.0, Worklets 0.12.1, RN 0.86.3, Fabric; FORCE_REACT_RENDER_FOR_SETTLED_ANIMATIONS enabled. Also confirmed against main 07aa7ab51, lines 146–178.

Verification is method-level with controlled setState, not a new device test. Searched existing issues; #7453 describes a different trigger/version.