fix(types): use f64 for GetChainTxStats tx_rate field

[deadmanoz]

Bitcoin Core has always returned txrate as a double since the RPC was added in v0.15 (PR #9733).

The previous type (i64) causes deserialisation to fail. Here's a minimal example:

use corepc_client::client_sync::v28::Client;
use corepc_client::client_sync::Auth;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let auth = Auth::UserPass("bitcoin".to_string(), "bitcoin".to_string());
    let client = Client::new_with_auth("http://127.0.0.1:8332", auth)?;
    let stats = client.get_chain_tx_stats()?;
    println!("tx_rate: {:?}", stats.tx_rate);
    Ok(())
}

Error: JsonRpc(Json(Error("invalid type: floating point `5.086614477523837`, expected i64", line: 1, column: 273)))

[jamillambert]

ACK 687119b

Thanks for the fix.

[jamillambert]

This should also be tested. It can be added to this PR or as a follow up.

[deadmanoz]

Updated existing test.

Switced to a Default wallet, and fund/mine so we get transactions to report meaningful data for assertion, e.g.

GetChainTxStats { 
  time: 1766036241,
  tx_count: 104,
  window_final_block_hash: 5d1f1967e8c133164a25a51f9bb125e79c8d2395baaabde8c3767b0220442a66,
  window_final_block_height: Some(102), 
  window_block_count: 101, 
  window_tx_count: Some(102), 
  window_interval: Some(17), 
  tx_rate: Some(6.0)
}

[jamillambert]

ACK 7ba4142

[tcharding]

ACK 7ba4142