feat(jupiter): rename jellyseerr profile to seerr

Jellyseerr was rebranded upstream to Seerr (seerr-team/seerr), and
nixpkgs now aliases services.jellyseerr to services.seerr with an
identical state directory, so this is a same-data rename. Also fixes
systemd.services.jellyseerr.after, which was a silent no-op since the
underlying unit has always been named seerr.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019MLWL7mWHCV6UGfzmhnfqN

machines/jupiter/environments.nix

@@ -17,7 +17,7 @@ _: {
     readarr.enable = true;
     sonarr.enable = true;
     jellyfin.enable = true;
-    jellyseerr.enable = true;
+    seerr.enable = true;
     immich.enable = true;
     development.enable = true;
     home-assistant.enable = true;