backup: migrate to native services.restic.backups

Replace custom backup-helper flake input with NixOS native
services.restic.backups module for ha1, monitoring01, and nixos-test1.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

flake.nix

@@ -9,10 +9,6 @@
       url = "github:Mic92/sops-nix";
       inputs.nixpkgs.follows = "nixpkgs-unstable";
     };
-    backup-helper = {
-      url = "git+https://git.t-juice.club/torjus/backup-helper?ref=master";
-      inputs.nixpkgs.follows = "nixpkgs-unstable";
-    };
     alerttonotify = {
       url = "git+https://git.t-juice.club/torjus/alerttonotify?ref=master";
       inputs.nixpkgs.follows = "nixpkgs-unstable";
@@ -29,7 +25,6 @@
       nixpkgs,
       nixpkgs-unstable,
       sops-nix,
-      backup-helper,
       alerttonotify,
       labmon,
       ...
@@ -136,7 +131,6 @@
             )
             ./hosts/nixos-test1
             sops-nix.nixosModules.sops
-            backup-helper.nixosModules.backup-helper
           ];
         };
         ha1 = nixpkgs.lib.nixosSystem {
@@ -153,7 +147,6 @@
             )
             ./hosts/ha1
             sops-nix.nixosModules.sops
-            backup-helper.nixosModules.backup-helper
           ];
         };
         template1 = nixpkgs.lib.nixosSystem {
@@ -234,7 +227,6 @@
             )
             ./hosts/monitoring01
             sops-nix.nixosModules.sops
-            backup-helper.nixosModules.backup-helper
             labmon.nixosModules.labmon
           ];
         };