feat(wm-revenue): #57 微信网厅（微信支付+AI客服+意图匹配）
- WxPayService: 统一下单/支付回调/退款/订单查询
- FaqService: FAQ CRUD/关键词搜索/热门推荐/分类查询
- IntentService: 意图识别(正则匹配)/批量解析/规则管理
- 3个Controller + 15+ API端点 (/api/revenue/wxpay|faq|intent/*)
- Entity: WxPayOrder, FaqItem, IntentRule
- DDL: rev_wx_pay_order/rev_faq_item/rev_intent_rule + 8个索引
- 8个单元测试
