Keeps Login V1 (also for a new instance) and turns off the service ping
that v4 sends to zitadel.com by default.

Based on nixpkgs PR 561044 (zitadel 4.17.3), built from source with
the console and protoc-gen-js 4.0.2; without the Login V2 app.

Each machine gets a backup.nix with its storage box sub-account
(coaxmetal sub2, styx sub3, acheron sub4, the yellow container sub5);
what is backed up is declared next to the services:

- coaxmetal: the hermes home without caches, toolchains, git clones,
node_modules and target dirs. Every *.db under .hermes (except cache/),
also in subdirs such as cron/ and the matrix crypto store, is dumped
with sqlite3 .backup into /var/backup/hermes, recreated each run so
removed databases don't linger; the live files are excluded.
- styx: n8n's DynamicUser state (/var/lib/private/n8n), its default
SQLite database dumped.
- acheron: zigbee2mqtt (devices, coordinator backup; database.db is JSON)
and mosquitto's retained messages as plain copies.
- yellow: jellyfin, sonarr, radarr, prowlarr, jellyseerr and sabnzbd
configs with their SQLite databases dumped. Excluded: jellyfin metadata,
logs and transcodes, servarr MediaCover and logs (also logs.db),
jellyseerr cache and logs, sabnzbd's incomplete Downloads and logs.
Media and downloads live in /var/download and are not backed up. A
missing database fails the hook instead of sqlite3 creating an empty one.

Grafana (coaxmetal, styx) is not backed up: datasources and dashboards
are provisioned from the repo, admin password and secret key come from
vars, anonymous users are viewers; both instances only have the four
provisioned dashboards.

Every machine now backs up into its own Hetzner storage box sub-account
(isolation: one machine's ssh key can't read or delete another's
archives), into ./borg in the sub-account's home. lass.backup.user replaces
lass.backup.repo and enables the job; host, port 23 and the box's host key
are module defaults, so a machine's backup.nix is only the sub-account.

Repos are always encrypted (repokey-blake2). The passphrase comes from a
per-machine clan vars generator borgbackup-repokey; it lives in the
password store, so passphrase + repo are enough to restore. The borgbackup
ssh key generator is unchanged.

neoprism moves to a new repo on u550643-sub1 (doInit creates it); the old
unencrypted repo u550643@...:/./neoprism is no longer referenced and is
removed by hand. Its paths, excludes and hooks are unchanged. The job stays
`hetzner`: with fresh repos nothing gains from a rename, and the unit name
is used for the postBackup hooks.

The timers get a fixed random delay of up to 1h after 03:00, so the
machines sharing the box don't all start at once.