jupiter: keep booting when the data array is missing

After the rack move one of the RAID0 disks failed to enumerate, and jupiter
boot-looped into an emergency shell nobody could use — root is locked, so
sulogin offers a prompt with no answer, and there is no ssh from there:

  Timed out waiting for device /dev/disk/by-uuid/dadbff6f-...
  Dependency failed for /mnt/data.
  Dependency failed for /var/lib/private/prowlarr.
  Dependency failed for Local File Systems.
  local-fs.target: Job local-fs.target/start failed with result 'dependency'
  Reached target Emergency Mode.

`nofail` on /mnt/data did not help, because the prowlarr and seerr bind
mounts layered on top of it had none: without it a mount is RequiredBy
local-fs.target, so those two failed the target on the array's behalf. Give
them `nofail` too and let them fail alone. `systemd.enableEmergencyMode =
false` then keeps a bad array from costing a reachable box at all — far more
useful on a headless host than a console prompt.

Booting further is only safe if nothing quietly relocates onto the 29G eMMC,
so pin the array-backed services to the mount. systemd derives
RequiresMountsFor from a unit's own paths, which for these is somewhere under
/var/lib (eMMC) — nothing pointed immich at mediaLocation or sabnzbd at its
configFile, so with the array gone they would have started and written to the
OS disk, into directories that go invisible the moment /mnt/data mounts over
them. jellyfin, sonarr, radarr and gitea already had a real dependency and
are untouched.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

hosts/jupiter/configuration.nix

@@ -63,6 +63,18 @@
     options = [ "nofail" ];  # don't block boot if the array is degraded/absent
   };
 
+  # `nofail` above is necessary but NOT sufficient — any mount layered on the
+  # array (prowlarr/seerr binds) is RequiredBy local-fs.target and will fail it
+  # regardless, and emergency mode on this box is a dead end: root is locked, so
+  # sulogin drops you at a prompt you cannot answer, with no ssh. 2026-08-06: a
+  # drive that failed to enumerate after the rack move did exactly this —
+  # "Timed out waiting for device /dev/disk/by-uuid/dadbff6f-…" -> Dependency
+  # failed for Local File Systems -> Reached target Emergency Mode, twice.
+  # Boot as far as possible instead and leave the failed units to be read over
+  # ssh. The array-backed services carry RequiresMountsFor=/mnt/data so they
+  # still refuse to start rather than writing to the eMMC.
+  systemd.enableEmergencyMode = false;
+
   # ---- Caddy vhosts (LAN) ----
   # Reached via pihole local-DNS names -> jupiter IP.
   services.caddy.virtualHosts = {