Restructure temp file write-execute-cleanup in performAutoUpdate so
cleanup is unconditionally reached after tryCatch captures any exec
error. Previously, the Windows and Unix paths each had separate
tryCatch+cleanup+rethrow sequences that could diverge under future
edits. Now a single tryCatch wraps the platform-branching exec, with
cleanup always running before any error is re-thrown.
Fixes#3306
Agent: security-auditor
Co-authored-by: B <6723574+louisgv@users.noreply.github.com>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
d1d51fb06d