fix(core): add null checks for timeout refs and event listeners for React 19 compatibility (#9116)

## Description
- Add null checks before clearTimeout calls in colorful-fallback.tsx, edgeless.dialog.tsx, and local.dialog.tsx
- Fix event listener cleanup in unfolding.tsx
- Update tsconfig.jsx to use react-jsx transform

## Testing
- [x] Verified type safety improvements for React 19 compatibility
- [x] Ensured proper cleanup of event listeners and timeouts
- [x] Confirmed no unintended side effects from the changes

Link to Devin run: https://app.devin.ai/sessions/2e790f3ea0d84402837ec6c3c6f83e4c

packages/frontend/component/src/components/internal-lottie/index.tsx

@@ -2,7 +2,7 @@ import type { AnimationItem } from 'lottie-web';
 import lottie from 'lottie-web';
 import { useEffect, useRef } from 'react';
 
-interface CustomLottieProps {
+export interface CustomLottieProps {
   options: {
     loop?: boolean | number | undefined;
     autoReverse?: boolean | undefined;
@@ -26,7 +26,7 @@ export const InternalLottie = ({
   height,
 }: CustomLottieProps) => {
   const element = useRef<HTMLDivElement>(null);
-  const lottieInstance = useRef<AnimationItem>();
+  const lottieInstance = useRef<AnimationItem | null>(null);
   const directionRef = useRef<1 | -1>(1);
 
   useEffect(() => {