SystemStatusEnum missing performance_issues case

[jbrooksuk]

Priority: P4 (Low - Nice to Have)

Problem

ComponentStatusEnum includes performance_issues, but SystemStatusEnum has no corresponding case. A system with components all in performance_issues state (but none in partial/major outage) would report as partial_outage via Status::current().

This is likely intentional but worth documenting.

Suggested Fix

Add a comment to Status::current() explaining that performance issues roll up to partial outage, or add a performance_issues case to SystemStatusEnum.