feat(configurations)!: flatten down, introduce meta.nix

Flatten down directory structure:
- From: `./hosts/${configuration-type}/${system}/{configuration,deploy}.nix`
-   To: `./hosts/${configuration-type}/{meta,configuration}.nix`
Keep `system` and `deploy-rs` config in `meta.nix`
Update `flake.lock`

hosts/nixos/__template__/meta.nix

@@ -0,0 +1,3 @@
+{
+  system = "x86_64-linux";
+}

hosts/nixos/homix/meta.nix

@@ -0,0 +1,3 @@
+{
+  system = "x86_64-linux";
+}

hosts/nixos/jeeves/configuration.nix

@@ -23,6 +23,7 @@
   # services.kanidm = { };
 
   age.rekey = {
+    # TODO: store in `meta`
     hostPubkey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIPopSTZ81UyKp9JSljCLp+Syk51zacjh9fLteqxQ6/aB";
     # masterIdentities = [ "${inputs.self}/secrets/privkey.age" ];
     # storageMode = "local";
@@ -74,7 +75,10 @@
 
   environment.systemPackages = with pkgs; [
     git
-    neovim
+    # FIXME: cannot deploy neovim-nightly
+    #                               V neovim source
+    #      > error: cannot add path '/nix/store/rhjznh5jdzdkzbnn0fhhvcf9rys0s59d-source' because it lacks a signature by a trusted key
+    # neovim
   ];
 
   # NOTE: made with `mkpasswd -m sha-512`

hosts/nixos/jeeves/home/jeeves.nix

@@ -16,7 +16,7 @@
 
   home.packages = with pkgs; [
     ## Core
-    neovim
+    # neovim
     git
     gnupg
     pciutils # lspci

hosts/nixos/jeeves/meta.nix

@@ -0,0 +1,48 @@
+{
+  # The `system` of the host
+  system = "x86_64-linux";
+
+  # `deploy-rs` configuration
+  deploy = {
+    # This is the hostname by which you'll refer to this machine using reploy-rs
+    hostname = "jeeves.reo101.xyz";
+
+    # This is the user that deploy-rs will use when connecting.
+    # This will default to your own username if not specified anywhere
+    sshUser = "jeeves";
+
+    # This is the user that the profile will be deployed to (will use sudo if not the same as above).
+    # If `sshUser` is specified, this will be the default (though it will _not_ default to your own username)
+    user = "root";
+
+    # Which sudo command to use. Must accept at least two arguments:
+    # the user name to execute commands as and the rest is the command to execute
+    # This will default to "sudo -u" if not specified anywhere.
+    sudo = "sudo -u";
+
+    # This is an optional list of arguments that will be passed to SSH.
+    sshOpts = [ "-p" "727" ];
+
+    # Fast connection to the node. If this is true, copy the whole closure instead of letting the node substitute.
+    # This defaults to `false`
+    fastConnection = false;
+
+    # If the previous profile should be re-activated if activation fails.
+    # This defaults to `true`
+    autoRollback = true;
+
+    # See the earlier section about Magic Rollback for more information.
+    # This defaults to `true`
+    magicRollback = true;
+
+    # The path which deploy-rs will use for temporary files, this is currently only used by `magicRollback` to create an inotify watcher in for confirmations
+    # If not specified, this will default to `/tmp`
+    # (if `magicRollback` is in use, this _must_ be writable by `user`)
+    tempPath = "/tmp";
+
+    # Build the derivation on the target system
+    # Will also fetch all external dependencies from the target system's substituters.
+    # This default to `false`
+    remoteBuild = true;
+  };
+}

hosts/nixos/x86_64-linux/jeeves/deploy.nix

@@ -1,42 +0,0 @@
-{
-  # This is the hostname by which you'll refer to this machine using reploy-rs
-  hostname = "jeeves.reo101.xyz";
-
-  # This is the user that deploy-rs will use when connecting.
-  # This will default to your own username if not specified anywhere
-  sshUser = "jeeves";
-
-  # This is the user that the profile will be deployed to (will use sudo if not the same as above).
-  # If `sshUser` is specified, this will be the default (though it will _not_ default to your own username)
-  user = "root";
-
-  # Which sudo command to use. Must accept at least two arguments:
-  # the user name to execute commands as and the rest is the command to execute
-  # This will default to "sudo -u" if not specified anywhere.
-  sudo = "sudo -u";
-
-  # This is an optional list of arguments that will be passed to SSH.
-  sshOpts = [ "-p" "727" ];
-
-  # Fast connection to the node. If this is true, copy the whole closure instead of letting the node substitute.
-  # This defaults to `false`
-  fastConnection = false;
-
-  # If the previous profile should be re-activated if activation fails.
-  # This defaults to `true`
-  autoRollback = true;
-
-  # See the earlier section about Magic Rollback for more information.
-  # This defaults to `true`
-  magicRollback = true;
-
-  # The path which deploy-rs will use for temporary files, this is currently only used by `magicRollback` to create an inotify watcher in for confirmations
-  # If not specified, this will default to `/tmp`
-  # (if `magicRollback` is in use, this _must_ be writable by `user`)
-  tempPath = "/tmp";
-
-  # Build the derivation on the target system
-  # Will also fetch all external dependencies from the target system's substituters.
-  # This default to `false`
-  remoteBuild = true;
-}