Archive: move indexer read-back to async task

[JoeHowarth]

This PR moves the indexer read-back verification to an asynchronous task to avoid blocking the main indexing flow. The change spawns a tokio task to perform the validation check for the first transaction in a block, allowing the indexing operation to complete without waiting for the verification to finish.

[Copilot]

Pull Request Overview

This PR moves the indexer read-back verification to an asynchronous task to avoid blocking the main indexing flow. The change spawns a tokio task to perform the validation check for the first transaction in a block, allowing the indexing operation to complete without waiting for the verification to finish.

Key Changes:

• Wrapped the transaction verification logic in a tokio::spawn async task
• Updated error logging format from {e} to {e:?} for better debug output

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[Copilot]

The spawned task does not handle potential panics or task failures. Consider using a named task handle or adding error logging if the spawned task fails, as errors in detached tasks can be silently lost.

[Copilot]

The spawned task captures first by move, but first may be used after this point in the parent function. Verify that first is not accessed after line 231, or clone it before spawning if needed.

Suggested change

	tokio::spawn({
	let tx_index_archiver = tx_index_archiver.clone();
	async move {
	if let Some(tx) = first {
	let first_for_spawn = first.clone();
	tokio::spawn({
	let tx_index_archiver = tx_index_archiver.clone();
	async move {
	if let Some(tx) = first_for_spawn {