PR #6499 merged without CI ever running on its head commit (fork run stayed
action_required), landing three bare `defer db.Close()` calls in
internal/setup/setup_test.go. The repo's errcheck config sets
disable-default-exclusions: true, so those are reported and golangci-lint has
been red on main ever since, failing every subsequent PR run.
Switch them to the codebase's existing convention
`defer func() { _ = db.Close() }()`.
wucm667