Fix memory leak when devtools is not installed

Editor assessment

Structurally correct but verbally redundant: 'fix(devtools): fix memory leak when devtools is not installed' says fix twice. Trim to 'avoid memory leak when devtools is not installed' and the subject reads better while staying imperative. The substance is good — the scope `devtools` is accurate, the scenario is clearly bounded to setups without devtools, and the `fix #4829` footer plus PR reference give full traceability. Memory leaks are exactly the kind of defect that deserves body text: a sentence on what retained the references, an event listener or global hook most likely, would make this a standalone record. As-is, spec parsing succeeds and changelog automation will treat it as a runtime patch under the devtools scope.