Hypothesis:
If we move to Rust for the function-evaluator, our service will be more stable, mightier, and more efficient in resource consumption.

Acceptance Criteria

• We flip the production evaluators from Node to Rust

Goals & Success Metrics

• Rust evaluators are in production, replacing Node-based ones
• Monotonic memory increase is no longer observed in production function evaluators
• Other performance metrics (evaluation runtime, memory consumption, CPU usage, etc.) are AT LEAST as good as current Node implementation

This is a follow-on Epic to T343720: If we create a working evaluator service in Rust, we can measure its performance and stability characteristics and plan to productionize it in a subsequent quarter, the work scheduled for 2026Q1 (July–September 2025); provisionally, this may be scheduled for 2026Q2 (October–December 2025), but is not confirmed yet.