fix: 平台消息身份传递 — AI-Core 收到正确昵称而非永远 fallback 到管理员

- forwardToAICore 新增 nickname 字段，格式 "昵称 (QQ号)" 明确标识发送者
- 解决非管理员用户 @昔涟 时 AI 仍认为是管理员的身份污染问题
- 同时包含：管理员群聊插入抑制、markdown 粗体剥离、SearXNG 容器、ethend 窗口隐藏

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

docker-compose.dev.db.yml

@@ -67,6 +67,18 @@ services:
       - "4222:4222"
       - "8222:8222"
 
+  # ========== SearXNG 搜索引擎 ==========
+  searxng:
+    image: searxng/searxng:latest
+    container_name: cyrene_searxng
+    volumes:
+      - ./searxng/settings.yml:/etc/searxng/settings.yml:ro
+    environment:
+      SEARXNG_SETTINGS_PATH: /etc/searxng/settings.yml
+    ports:
+      - "8088:8080"
+    restart: unless-stopped
+
 volumes:
   pg_data:
   redis_data: