feat: SearXNG 搜索集成 + DevTools Docker + PG 备份 + 文档更新

- web_search 工具/插件接入自托管 SearXNG，支持百度/必应/搜狗/360搜索
- DevTools 加入 docker-compose.dev.yml，devtools/Dockerfile
- scripts/pg-backup.sh 数据库备份恢复脚本，docs/pg-backup-migration.md
- 后台思考 + datetime 插件时区默认 Asia/Shanghai
- docker-compose 对齐 volume 名称，清理 tool-engine 残留引用
- README.md / Deploy.md 更新至当前架构（移除简报/tool-engine，新增搜索/跨端同步/DevTools）

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

docker-compose.yml

@@ -2,6 +2,15 @@
 version: '3.8'
 
 services:
+  # ========== 搜索引擎 ==========
+  searxng:
+    image: searxng/searxng:latest
+    volumes:
+      - ./searxng/settings.yml:/etc/searxng/settings.yml:ro
+    environment:
+      SEARXNG_SETTINGS_PATH: /etc/searxng/settings.yml
+    restart: unless-stopped
+
   # ========== 反向代理 ==========
   caddy:
     image: caddy:2-alpine
@@ -25,7 +34,6 @@ services:
       JWT_EXPIRY_HOURS: "720"
       AI_CORE_URL: http://ai-core:8081
       MEMORY_SERVICE_URL: http://memory-service:8091
-      TOOL_ENGINE_URL: http://tool-engine:8092
       VOICE_SERVICE_URL: http://voice-service:8093
       IOT_DEBUG_SERVICE_URL: http://iot-debug-service:8083
       POSTGRES_HOST: postgres
@@ -52,6 +60,7 @@ services:
       LLM_API_KEY: ${LLM_API_KEY}
       LLM_MODEL: ${LLM_MODEL:-gpt-4o}
       LLM_FALLBACK_MODEL: ${LLM_FALLBACK_MODEL:-gpt-4o-mini}
+      SEARXNG_URL: http://searxng:8080
       POSTGRES_HOST: postgres
       POSTGRES_PORT: "5432"
       POSTGRES_USER: ${POSTGRES_USER:-cyrene}
@@ -76,18 +85,6 @@ services:
         condition: service_healthy
     restart: unless-stopped
 
-  tool-engine:
-    build: ./backend/tool-engine
-    environment:
-      PORT: "8092"
-      IOT_SERVICE_URL: http://iot-debug-service:8083
-      DATA_DIR: /tmp/cyrene_data
-      DB_URL: "postgres://${POSTGRES_USER:-cyrene}:${POSTGRES_PASSWORD}@postgres:5432/${POSTGRES_DB:-cyrene_ai}?sslmode=disable"
-    depends_on:
-      postgres:
-        condition: service_healthy
-    restart: unless-stopped
-
   voice-service:
     build: ./backend/voice-service
     environment: