Fix memory leak from uncancelled timeouts in Share component

[Copilot]

The Share component's setTimeout calls were not cleaned up on unmount, causing React to attempt state updates on unmounted components.

Changes:

• Store timeout ID in ref for lifecycle management
• Add useEffect cleanup to cancel pending timeout on unmount
• Clear existing timeout before setting new one to prevent concurrent timeouts

const timeoutRef = useRef(null);

useEffect(() => {
  return () => {
    if (timeoutRef.current) {
      clearTimeout(timeoutRef.current);
    }
  };
}, []);

const handleShare = async (e) => {
  // Clear any existing timeout before setting a new one
  if (timeoutRef.current) {
    clearTimeout(timeoutRef.current);
  }

  await shareHandler({
    onSuccess: (message) => {
      timeoutRef.current = setTimeout(() => {
        setShareStatus({ type: null, message: "" });
      }, 3000);
    },
    // ...
  });
};

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