fix(eval): reflow evaluators_safety_test imports to satisfy rustfmt

[jwesleye]

Summary

Tiny follow-up: integration's `cargo fmt --check` fails on `eval/tests/evaluators_safety_test.rs:12` because rustfmt reflows the import block differently. This PR runs cargo fmt and pushes the fix.

Cause

The import block arrived via PR #821's US1c merge + reconciliation commit 6776a9a. I added `Aggregator` in a companion rescue path (PR #823 branch) without re-running fmt on the file.

Test plan

• `cargo fmt --check -p swink-agent-eval` clean

🤖 Generated with Claude Code

[github-actions]

Benchmark comparison

group                                    base                                   pr
-----                                    ----                                   --
compact_sliding_window/heavy_500_msgs    1.00     84.7±1.80µs        ? ?/sec    1.00     84.5±1.88µs        ? ?/sec
compact_sliding_window/no_op_100_msgs    1.01      2.6±0.12µs        ? ?/sec    1.00      2.6±0.07µs        ? ?/sec

[github-actions]

Benchmark comparison

group                                    base                                   pr
-----                                    ----                                   --
compact_sliding_window/heavy_500_msgs    1.03     91.5±0.67µs        ? ?/sec    1.00     88.9±0.91µs        ? ?/sec
compact_sliding_window/no_op_100_msgs    1.00      2.7±0.08µs        ? ?/sec    1.02      2.7±0.15µs        ? ?/sec