feat: Add 7 new stacks (Batch 2)

Added stacks:
- nextcloud-aio (Cloud storage)
- wordpress (CMS)
- searxng (Meta search)
- authentik (SSO provider)
- jellyfin (Media server)

All stacks include:
- compose.yml with proper configuration
- README.md with deployment info
- stack.toml for Komodo Resource Sync

stacks/nextcloud-aio/README.md

@@ -0,0 +1,24 @@
+# Nextcloud AIO
+
+☁️ Cloud Storage & Collaboration
+
+## Deploy in Komodo
+
+**Pfad:** `stacks/nextcloud-aio/`
+
+## Ports
+
+- `8080` - Web UI
+
+## Caddy
+
+```caddyfile
+cloud.example.com {
+    reverse_proxy localhost:8080
+}
+```
+
+## Notes
+
+- All-In-One Image mit Apache, PHP, DB
+- Erster Start dauert länger (Setup)