The coreio.Local.Delete error wraps the underlying os.ErrNotExist
through core.E, so the prior os.IsNotExist check on the registry
Unregister path never matched. Same wrapping broke the daemon
Stop path that relied on pidfile.Release being a no-op for absent
files.
Switch both to coreio.Local.Exists before Delete, which is the
idempotent pattern the callers already assume. Adds coverage for
TestPIDFile_Release_MissingIsNoop and fixes TestRegistry_Unregister
MissingIsNoop.
Co-Authored-By: Virgil <virgil@lethean.io>
PIDFile manages a process ID lock file with Acquire/Release semantics.
Detects stale PIDs via signal(0) probe, creates parent directories
automatically. Includes standalone ReadPID helper for checking if a
PID file's process is still alive.
Co-Authored-By: Virgil <virgil@lethean.io>
