homelab-deploy: enable prometheus metrics

- Update homelab-deploy input to get metrics support
- Enable metrics endpoint on port 9972
- Add scrape target for prometheus auto-discovery

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

flake.lock

@@ -28,11 +28,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1770443536,
-        "narHash": "sha256-UufZIVggiioMFDSjKx+ifgkDOk9alNSiRmkvc4/+HIA=",
+        "lastModified": 1770447502,
+        "narHash": "sha256-xH1PNyE3ydj4udhe1IpK8VQxBPZETGLuORZdSWYRmSU=",
         "ref": "master",
-        "rev": "95b795dcfd86b7b36045bba67e536b3a1c61dd33",
-        "revCount": 20,
+        "rev": "79db119d1ca6630023947ef0a65896cc3307c2ff",
+        "revCount": 22,
         "type": "git",
         "url": "https://git.t-juice.club/torjus/homelab-deploy"
       },

system/homelab-deploy.nix

@@ -19,8 +19,15 @@ in
       natsUrl = "nats://nats1.home.2rjus.net:4222";
       nkeyFile = "/run/secrets/homelab-deploy-nkey";
       flakeUrl = "git+https://git.t-juice.club/torjus/nixos-servers.git";
+      metrics.enable = true;
     };
 
+    # Expose metrics for Prometheus scraping
+    homelab.monitoring.scrapeTargets = [{
+      job_name = "homelab-deploy";
+      port = 9972;
+    }];
+
     # Ensure listener starts after vault secret is available
     systemd.services.homelab-deploy-listener = {
       after = [ "vault-secret-homelab-deploy-nkey.service" ];