feat(x1): add secrets management and configuration

Introduce encrypted secrets and SOPS configuration for the x1 system. Update SSH and related services to utilize these secrets and modify flake.lock to align with the latest dependencies.

flake.lock

@@ -388,11 +388,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1742655702,
-        "narHash": "sha256-jbqlw4sPArFtNtA1s3kLg7/A4fzP4GLk9bGbtUJg0JQ=",
+        "lastModified": 1743387206,
+        "narHash": "sha256-24N3NAuZZbYqZ39NgToZgHUw6M7xHrtrAm18kv0+2Wo=",
         "owner": "nix-community",
         "repo": "home-manager",
-        "rev": "0948aeedc296f964140d9429223c7e4a0702a1ff",
+        "rev": "15c5f9d04fabd176f30286c8f52bbdb2c853a146",
         "type": "github"
       },
       "original": {
@@ -799,11 +799,11 @@
     },
     "nixpkgs_4": {
       "locked": {
-        "lastModified": 1742751704,
-        "narHash": "sha256-rBfc+H1dDBUQ2mgVITMGBPI1PGuCznf9rcWX/XIULyE=",
+        "lastModified": 1743576891,
+        "narHash": "sha256-vXiKURtntURybE6FMNFAVpRPr8+e8KoLPrYs9TGuAKc=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "f0946fa5f1fb876a9dc2e1850d9d3a4e3f914092",
+        "rev": "44a69ed688786e98a101f02b712c313f1ade37ab",
         "type": "github"
       },
       "original": {
@@ -2818,11 +2818,11 @@
     },
     "unstable": {
       "locked": {
-        "lastModified": 1742669843,
-        "narHash": "sha256-G5n+FOXLXcRx+3hCJ6Rt6ZQyF1zqQ0DL0sWAMn2Nk0w=",
+        "lastModified": 1743583204,
+        "narHash": "sha256-F7n4+KOIfWrwoQjXrL2wD9RhFYLs2/GGe/MQY1sSdlE=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "1e5b653dff12029333a6546c11e108ede13052eb",
+        "rev": "2c8d3f48d33929642c1c12cd243df4cc7d2ce434",
         "type": "github"
       },
       "original": {