- Introduce a new subscription kind `transactionReceipts` to allow clients to
receive transaction receipts over WebSocket as soon as they are available.
- Accept optional `transactionHashes` filter to subscribe to receipts for specific
transactions; an empty or omitted filter subscribes to all receipts.
- Preserve the same receipt format as returned by `eth_getTransactionReceipt`.
- Avoid additional HTTP polling, reducing RPC load and latency.
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Co-authored-by: Sina Mahmoodi <itz.s1na@gmail.com>