Rename Node Exporter dashboard to macOS

The dashboard now uses Grafana Alloy instead of node_exporter, so the
name no longer makes sense. Simplified to just "macOS".

- Renamed file: node-exporter-macos.json -> macos.json
- Updated title: "Node Exporter - macOS" -> "macOS"
- Updated uid: "node-exporter-macos" -> "macos"
- Removed "node-exporter" from tags

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

ansible/roles/grafana/files/dashboards/macos.json

@@ -1248,7 +1248,7 @@
   ],
   "refresh": "30s",
   "schemaVersion": 38,
-  "tags": ["node-exporter", "macos", "darwin"],
+  "tags": ["macos", "darwin"],
   "templating": {
     "list": [
       {
@@ -1319,8 +1319,8 @@
   },
   "timepicker": {},
   "timezone": "browser",
-  "title": "Node Exporter - macOS",
-  "uid": "node-exporter-macos",
+  "title": "macOS",
+  "uid": "macos",
   "version": 1,
   "weekStart": ""
 }