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/channels.json

@@ -0,0 +1,40 @@
+{
+  "name": "Channels DVR Server",
+  "slug": "channels",
+  "categories": [
+    13
+  ],
+  "date_created": "2024-05-02",
+  "type": "ct",
+  "updateable": false,
+  "privileged": true,
+  "interface_port": 8089,
+  "documentation": "https://getchannels.com/docs/getting-started/quick-start-guide/",
+  "website": "https://getchannels.com/dvr-server/",
+  "logo": "https://cdn.jsdelivr.net/gh/selfhst/icons@main/webp/channels-dvr.webp",
+  "config_path": "",
+  "description": "Channels DVR Server runs on your computer or NAS device at home. There's no cloud to worry about. Your tv shows and movies will always be available.",
+  "install_methods": [
+    {
+      "type": "default",
+      "script": "ct/channels.sh",
+      "resources": {
+        "cpu": 2,
+        "ram": 1024,
+        "hdd": 8,
+        "os": "debian",
+        "version": "13"
+      }
+    }
+  ],
+  "default_credentials": {
+    "username": null,
+    "password": null
+  },
+  "notes": [
+    {
+      "text": "WARNING: Installation sources scripts outside of Community Scripts repo. Please check the source before installing.",
+      "type": "warning"
+    }
+  ]
+}