pasteurize

Diagnose and fix a hard bug. Build a reliable reproduction, name the cause, add a regression test, and apply the minimum fix. Use when the user reports a bug, a failure, a flaky test, a performance regression, an error, or a wrong result whose cause is unknown. Use when the user pastes a symptom, a stack trace, or failing test output. Use for "why is X broken", "it stopped working", "it got slower", or "this looks…