getFees (removed)

getFees combined a recent blockhash, its legacy fee calculator, and a last valid slot in one response.

Migration

1. Call getLatestBlockhash to obtain blockhash and lastValidBlockHeight. The replacement reports a block height, not the legacy lastValidSlot.
2. Compile the transaction message with that blockhash, then pass the encoded message to getFeeForMessage.

Use lastValidBlockHeight when tracking transaction expiration; do not convert it to a slot or fixed wall-clock deadline.