refactor: remove frontend, move JSONs to json/ top-level

- Archive frontend to community-scripts/ProxmoxVE-Frontend-Archive
- Move frontend/public/json/ -> json/
- Update workflow paths in 5 actions:
  - update-versions-github.yml
  - update-json-date.yml
  - push-json-to-pocketbase.yml
  - delete-pocketbase-entry-on-removal.yml
  - autolabeler.yml
- Remove frontend-cicd.yml (no longer needed)
- Clean up .gitignore (remove frontend-specific entries)

json/adguardhome-sync.json

@@ -0,0 +1,59 @@
+{
+  "name": "AdGuardHome-Sync",
+  "slug": "adguardhome-sync",
+  "categories": [
+    5
+  ],
+  "date_created": "2025-12-13",
+  "type": "addon",
+  "updateable": true,
+  "privileged": false,
+  "interface_port": 8080,
+  "documentation": "https://github.com/bakito/adguardhome-sync",
+  "website": "https://github.com/bakito/adguardhome-sync",
+  "logo": "https://cdn.jsdelivr.net/gh/selfhst/icons@main/webp/adguardhome-sync.webp",
+  "config_path": "/opt/adguardhome-sync/adguardhome-sync.yaml",
+  "description": "Synchronize AdGuardHome config to one or multiple replica instances. Syncs General Settings, Filters, Rewrites, Services, Clients, DNS Config, DHCP Config and Theme.",
+  "install_methods": [
+    {
+      "type": "default",
+      "script": "tools/addon/adguardhome-sync.sh",
+      "resources": {
+        "cpu": null,
+        "ram": null,
+        "hdd": null,
+        "os": null,
+        "version": null
+      }
+    },
+    {
+      "type": "alpine",
+      "script": "tools/addon/adguardhome-sync.sh",
+      "resources": {
+        "cpu": null,
+        "ram": null,
+        "hdd": null,
+        "os": null,
+        "version": null
+      }
+    }
+  ],
+  "default_credentials": {
+    "username": null,
+    "password": null
+  },
+  "notes": [
+    {
+      "text": "Edit /opt/adguardhome-sync/adguardhome-sync.yaml to configure your AdGuardHome instances",
+      "type": "info"
+    },
+    {
+      "text": "Origin = Primary instance, Replicas = Instances to sync to",
+      "type": "info"
+    },
+    {
+      "text": "Update with: update_adguardhome-sync",
+      "type": "info"
+    }
+  ]
+}