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/koel.json

@@ -0,0 +1,48 @@
+{
+  "name": "Koel",
+  "slug": "koel",
+  "categories": [
+    13
+  ],
+  "date_created": "2025-12-15",
+  "type": "ct",
+  "updateable": true,
+  "privileged": false,
+  "interface_port": 80,
+  "documentation": "https://docs.koel.dev/",
+  "config_path": "/opt/koel/.env",
+  "website": "https://koel.dev/",
+  "logo": "https://cdn.jsdelivr.net/gh/selfhst/icons@main/webp/koel-light.webp",
+  "description": "Koel is a simple web-based personal audio streaming service written in Vue and Laravel. It supports multiple users, audio visualization, smart playlists, YouTube integration, and Last.fm scrobbling.",
+  "install_methods": [
+    {
+      "type": "default",
+      "script": "ct/koel.sh",
+      "resources": {
+        "cpu": 2,
+        "ram": 2048,
+        "hdd": 8,
+        "os": "Debian",
+        "version": "13"
+      }
+    }
+  ],
+  "default_credentials": {
+    "username": "admin@koel.dev",
+    "password": "KoelIsCool"
+  },
+  "notes": [
+    {
+      "text": "Media files should be placed in /opt/koel_media",
+      "type": "info"
+    },
+    {
+      "text": "Database credentials are stored in ~/koel.creds",
+      "type": "info"
+    },
+    {
+      "text": "Music library is scanned hourly via cron job",
+      "type": "info"
+    }
+  ]
+}