Build a live cricket score widget

• Shows the teams, current score (runs/wickets), overs completed, run rate and batters' scores, updated as new data arrives
• Receives updates by polling every few seconds with setTimeout chaining, or by EventSource; polling stops when the tab is hidden and resumes when it is visible again
• A ball-by-ball list for the current over (0, 1, 4, 6, W, wide and so on as coloured badges) and a summary of the last completed overs
• A stale-data indicator appears when no successful update has arrived for a set time (for example 15 seconds), and clears on recovery; failures do not blank the last known score
• New events are merged by ball id so duplicates or out-of-order updates do not double count
• Connection or polling is cleaned up on unmount, and score changes are announced with a polite live region without flooding

Only after every requirement works.

• Exponential backoff with jitter on errors
• Highlight changed values with a brief animation
• Multiple matches with a selector