build: package local admin service

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docker-compose.example.yml

@@ -0,0 +1,9 @@
+services:
+  sync:
+    build: .
+    env_file: .env
+    ports:
+      - "8080:8080"
+    volumes:
+      - ./data:/data
+    restart: unless-stopped