Adds ReadarrEvent::GetLogs backed by get_readarr_logs, which formats each
record into the Readarr logs list, and surfaces it as
'readarr list logs --events N'.
The --output-in-log-format branch reads the Readarr log lines, and is
covered by a test that pins that source so it cannot silently drift to
another servarr's data.
Adds ReadarrEvent::GetUpdates backed by get_readarr_updates, rendering the
update history into the Readarr updates view, and surfaces it as
'readarr list updates'.
Covers the case where an update record omits the changes key, which the
live instance returns for its most recent release.
Add ReadarrEvent::GetDiskSpace, mapped to GET /diskspace, and
get_readarr_diskspace, which stores the result on ReadarrData for the
root folder and system views.
Surface it as `managarr readarr list disk-space`, matching the other
three servarrs.
Readarr returns a label field on some records that DiskSpace does not
model; serde drops it, so the CLI prints only the path and the free and
total space, as it does for the other three servarrs.
Dark-Alex-17