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/inventree.json

@@ -0,0 +1,40 @@
+{
+  "name": "InvenTree",
+  "slug": "inventree",
+  "categories": [
+    25
+  ],
+  "date_created": "2025-03-06",
+  "type": "ct",
+  "updateable": true,
+  "privileged": false,
+  "interface_port": 80,
+  "documentation": "https://docs.inventree.org/en/latest/",
+  "website": "https://inventree.org",
+  "logo": "https://cdn.jsdelivr.net/gh/selfhst/icons@main/webp/inventree.webp",
+  "config_path": "/etc/inventree/",
+  "description": "InvenTree is an open-source inventory management system which provides intuitive parts management and stock control. It is designed to be lightweight and easy to use for SME or hobbyist applications.",
+  "install_methods": [
+    {
+      "type": "default",
+      "script": "ct/inventree.sh",
+      "resources": {
+        "cpu": 2,
+        "ram": 2048,
+        "hdd": 6,
+        "os": "ubuntu",
+        "version": "24.04"
+      }
+    }
+  ],
+  "default_credentials": {
+    "username": "admin",
+    "password": "`cat /etc/inventree/admin_password.txt`"
+  },
+  "notes": [
+    {
+      "text": "Please read the documentation for your configuration needs.",
+      "type": "info"
+    }
+  ]
+}