#364's `use super::*;` removal stripped the test module's view of
`LogEvent`, `Reporter`, `Stage`, `StageLog`, and `Lockfile`, but the
test bodies still reference them — so `cargo nextest run -p
pacquet-package-manager` failed to compile on `main`.
Promote the inline `use pacquet_lockfile::Lockfile` from
`frozen_lockfile_flag_overrides_config_lockfile_false` to the module-
level `use` block, and add the missing reporter symbols alongside the
existing `SilentReporter` import. The two `Lockfile`-using tests now
share one import.