fix backtest legacy replacements, log tweak

[dvush]

📝 Summary

💡 Motivation and Context

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✅ I have completed the following steps:

• Run make lint
• Run make test
• Added tests (if applicable)

[Copilot]

Pull Request Overview

This PR fixes legacy replacements in the backtest module and adjusts log levels for non-positive block values and unique coinbase profits.

• Change log levels from warn to info in the redistribution module.
• Add a new enum variant "Replaced" and update order filtering logic based on order inclusion and replacement.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
crates/rbuilder/src/backtest/redistribute/mod.rs	Updated log severity from warn to info when block value or profit isn’t positive.
crates/rbuilder/src/backtest/mod.rs	Added a new "Replaced" enum variant and refined order filtering logic to correctly handle replaced orders.

Comments suppressed due to low confidence (3)

crates/rbuilder/src/backtest/redistribute/mod.rs:783

• The log level was changed from warn to info for a condition that might indicate an issue. Please confirm that the lowered severity is intentional and that monitoring tools do not rely on warning-level alerts here.

info!(?address1, ?address2, newly_included_orders = ?result.new_orders_included, "Joint block value delta is not positive");

crates/rbuilder/src/backtest/mod.rs:161

• The log message has been updated to 'order was replaced' when filtering orders. Confirm that this change clearly reflects the new filtering reason and that downstream log processing or alerting logic is updated accordingly.

trace!(order = ?id, "order was replaced");

crates/rbuilder/src/backtest/mod.rs:116

• Consider adding tests to verify that orders present in the included orders set are not filtered out, and that the new replacement logic behaves correctly in various scenarios.

// we never filter included orders even by timestamp