Improve transaction persistence UX and accessibility

[meenakshi30-code]

-What changed

Added defensive localStorage parsing to prevent crashes
Fixed minor UI issue in empty state button
Improved accessibility using aria-live for persisted data

Why
Transactions are persisted using localStorage, but corrupted data
or missing UI feedback could affect UX.
This PR improves stability and polish without changing core logic.

Closes #6

[vercel]

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[github-actions]

🎉 Thanks for the PR, @meenakshi30-code!

We really appreciate you taking the time to contribute to OpenPlayground! 💙

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[meenakshi30-code]

I'm having bit difficulty in solving the conflicts for this issue.
I'll try to solve it by tommorrow :(

[Renu-code123]

@meenakshi30-code, okay, resolve the conflict as soon as possible