LND's admin.macaroon is owned by a rootless-podman subordinate UID
(typically 100000) with mode 640. The archipelago server runs as UID
1000 and cannot read the file directly, which caused every dashboard
LND RPC (getinfo, connect-info, export-channel-backup) and lnd_client
to fail with "Failed to read LND admin macaroon".
Add a read_lnd_admin_macaroon() helper that first tries a direct read
(for operators who have relaxed permissions) then falls back to
`sudo -n cat`, mirroring the pattern already used for Tor hidden
service hostnames in handle_lnd_connect_info. Centralise the canonical
macaroon path as LND_ADMIN_MACAROON_PATH and route all four callers
through the helper.
Verified on .228: GET /lnd-connect-info now returns 200 with cert,
macaroon, and tor_onion fields. Dashboard QR/connect-string UI
unblocked.
be96002372