feat(chat): 新增聊天调用日志与动态配置支持

- 新增 KeyboardUserCallLog 实体及对应 Mapper、Service，用于记录每次聊天请求的模型、token、耗时、错误码等
- ChatController.talk() 在流式输出前后采集元数据，异步落库，支持错误码记录
- AppConfig 新增 QdrantConfig，支持 vectorSearchLimit 动态配置
- QdrantVectorService 改为从 Nacos 动态读取搜索条数，替代硬编码 limit=1
- UserController 登出时先清除用户会话再清除 token，避免并发异常

src/main/resources/mapper/KeyboardUserCallLogMapper.xml

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
+<mapper namespace="com.yolo.keyborad.mapper.KeyboardUserCallLogMapper">
+  <resultMap id="BaseResultMap" type="com.yolo.keyborad.model.entity.KeyboardUserCallLog">
+    <!--@mbg.generated-->
+    <!--@Table keyboard_user_call_log-->
+    <id column="id" jdbcType="BIGINT" property="id" />
+    <result column="user_id" jdbcType="BIGINT" property="userId" />
+    <result column="request_id" jdbcType="VARCHAR" property="requestId" />
+    <result column="feature" jdbcType="VARCHAR" property="feature" />
+    <result column="model" jdbcType="VARCHAR" property="model" />
+    <result column="input_tokens" jdbcType="INTEGER" property="inputTokens" />
+    <result column="output_tokens" jdbcType="INTEGER" property="outputTokens" />
+    <result column="total_tokens" jdbcType="INTEGER" property="totalTokens" />
+    <result column="success" jdbcType="BOOLEAN" property="success" />
+    <result column="latency_ms" jdbcType="INTEGER" property="latencyMs" />
+    <result column="error_code" jdbcType="VARCHAR" property="errorCode" />
+    <result column="created_at" jdbcType="TIMESTAMP" property="createdAt" />
+  </resultMap>
+  <sql id="Base_Column_List">
+    <!--@mbg.generated-->
+    id, user_id, request_id, feature, model, input_tokens, output_tokens, total_tokens, 
+    success, latency_ms, error_code, created_at
+  </sql>
+</mapper>