Prepare config for flake usage

installer/template-configuration.nix

@@ -1,25 +0,0 @@
-{ ... }:
-let
-  host = "generic";
-  stateVersion = "25.05";
-
-  repo = builtins.fetchGit {
-    url = "https://forgejo.sinerva.eu/VSinerva/nixos-conf.git";
-    name = "nixos-conf-forgejo";
-    ref = "main";
-  };
-in
-{
-  imports = [
-    ./hardware-configuration.nix
-    "${repo}/hosts/${host}.nix"
-  ];
-
-  # This value determines the NixOS release from which the default
-  # settings for stateful data, like file locations and database versions
-  # on your system were taken. It‘s perfectly fine and recommended to leave
-  # this value at the release version of the first install of this system.
-  # Before changing this value read the documentation for this option
-  # (e.g. man configuration.nix or on https://nixos.org/nixos/options.html).
-  system.stateVersion = stateVersion; # Did you read the comment?
-}

shared/base.nix

@@ -46,9 +46,9 @@
         ZSH_TMUX_CONFIG=/etc/tmux.conf
       '';
       promptInit = ''
-        if [ -n "$IN_NIX_SHELL" ]; then 
+        if [ "$SHLVL" "!= 1" ]; then 
           setopt PROMPT_SUBST
-          RPROMPT+='[nix]'
+          RPROMPT+='[depth-$\{SHLVL\}]'
         fi
       '';
     };
@@ -131,6 +131,7 @@
     ######################################## Housekeeping ###########################################
     system.autoUpgrade = {
       enable = true;
+      flake = "git+https://gitea.sinerva.eu/VSinerva/nixos-conf.git?ref=main&shallow=1";
       dates = "04:00";
       randomizedDelaySec = "30min";
       allowReboot = true;
@@ -147,7 +148,6 @@
           "flakes"
         ];
         auto-optimise-store = true;
-        tarball-ttl = 0;
       };
       gc = {
         automatic = true;