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/authentik/compose.yml

@@ -0,0 +1,55 @@
+services:
+  authentik:
+    image: ghcr.io/goauthentik/server:latest
+    container_name: authentik
+    restart: unless-stopped
+    ports:
+      - "127.0.0.1:9000:9000"
+      - "127.0.0.1:9443:9443"
+    volumes:
+      - authentik_media:/media
+      - authentik_custom:/custom-templates
+    environment:
+      - AUTHENTIK_SECRET_KEY=change-me-to-random-secret
+      - AUTHENTIK_REDIS__HOST=authentik-redis
+      - AUTHENTIK_POSTGRESQL__HOST=authentik-db
+      - AUTHENTIK_POSTGRESQL__USER=authentik
+      - AUTHENTIK_POSTGRESQL__NAME=authentik
+      - AUTHENTIK_POSTGRESQL__PASSWORD=authentik
+    depends_on:
+      - authentik-db
+      - authentik-redis
+    networks:
+      - authentik-network
+
+  authentik-db:
+    image: postgres:15
+    container_name: authentik-db
+    restart: unless-stopped
+    volumes:
+      - authentik_db:/var/lib/postgresql/data
+    environment:
+      - POSTGRES_USER=authentik
+      - POSTGRES_PASSWORD=authentik
+      - POSTGRES_DB=authentik
+    networks:
+      - authentik-network
+
+  authentik-redis:
+    image: redis:alpine
+    container_name: authentik-redis
+    restart: unless-stopped
+    volumes:
+      - authentik_redis:/data
+    networks:
+      - authentik-network
+
+volumes:
+  authentik_media:
+  authentik_custom:
+  authentik_db:
+  authentik_redis:
+
+networks:
+  authentik-network:
+    driver: bridge