homelab: add deploy.enable option with assertion

- Add homelab.deploy.enable option (requires vault.enable)
- Create shared homelab-deploy Vault policy for all hosts
- Enable homelab.deploy on all vault-enabled hosts

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

flake.lock

@@ -28,11 +28,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1770442013,
-        "narHash": "sha256-JZbm6X0A770bb+VlbJYvRHrVqWOSsmu6Hn4B8nvsPc8=",
+        "lastModified": 1770443536,
+        "narHash": "sha256-UufZIVggiioMFDSjKx+ifgkDOk9alNSiRmkvc4/+HIA=",
         "ref": "master",
-        "rev": "71d6aa8b614f557d029bfc2e64375c812ed7bc10",
-        "revCount": 19,
+        "rev": "95b795dcfd86b7b36045bba67e536b3a1c61dd33",
+        "revCount": 20,
         "type": "git",
         "url": "https://git.t-juice.club/torjus/homelab-deploy"
       },