flatten app to repo root and update docker deployment for single-stack runtime

docker-compose.yml

@@ -1,7 +1,7 @@
 services:
   app:
     build:
-      context: ./frontend
+      context: .
       dockerfile: Dockerfile
       args:
         NEXT_PUBLIC_API_URL: ${NEXT_PUBLIC_API_URL:-}
@@ -17,5 +17,15 @@ services:
       OPENCLAW_API_KEY: ${OPENCLAW_API_KEY:-}
       OPENCLAW_MODEL: ${OPENCLAW_MODEL:-zeroclaw}
       SEC_USER_AGENT: ${SEC_USER_AGENT:-Fiscal Clone <support@fiscal.local>}
+    healthcheck:
+      test: ["CMD-SHELL", "wget -q --spider http://localhost:3000/api/health || exit 1"]
+      interval: 30s
+      timeout: 10s
+      retries: 3
     ports:
-      - '3000:3000'
+      - '${APP_PORT:-3000}:3000'
+    volumes:
+      - app_data:/app/data
+
+volumes:
+  app_data: