feat(chat): 重构 LLM 流式输出并扩展 ChatSaveReq 字段

- 将原始整段 chunk 拆分为 3 字批次推送，降低前端卡顿
- ChatSaveReq 新增 userId、lang、liked 等 8 个字段并补充 Swagger 注解
- QdrantVectorService 改用 Map<String,JsonWithInt.Value> 载荷，新增 QdrantPayloadMapper 统一转换

src/main/java/com/yolo/keyborad/mapper/QdrantPayloadMapper.java

@@ -0,0 +1,61 @@
+package com.yolo.keyborad.mapper;
+
+
+
+import com.yolo.keyborad.model.dto.chat.ChatSaveReq;
+import io.qdrant.client.grpc.JsonWithInt;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class QdrantPayloadMapper {
+
+    public static Map<String, JsonWithInt.Value> toQdrantPayload(ChatSaveReq p) {
+        Map<String, JsonWithInt.Value> map = new HashMap<>();
+
+        if (p.getUserId() != null)
+            map.put("userId", longValue(p.getUserId()));
+
+        if (p.getUserText() != null)
+            map.put("userText", stringValue(p.getUserText()));
+
+        if (p.getReplyText() != null)
+            map.put("replyText", stringValue(p.getReplyText()));
+
+        if (p.getCharacterId() != null)
+            map.put("characterId", intValue(p.getCharacterId()));
+
+        if (p.getLang() != null)
+            map.put("lang", stringValue(p.getLang()));
+
+        if (p.getLiked() != null)
+            map.put("liked", boolValue(p.getLiked()));
+
+        if (p.getCreatedAt() != null)
+            map.put("createdAt", longValue(p.getCreatedAt()));
+
+        if (p.getSource() != null)
+            map.put("source", stringValue(p.getSource()));
+
+        if (p.getAppVersion() != null)
+            map.put("appVersion", stringValue(p.getAppVersion()));
+
+        return map;
+    }
+
+    private static JsonWithInt.Value stringValue(String v) {
+        return JsonWithInt.Value.newBuilder().setStringValue(v).build();
+    }
+
+    private static JsonWithInt.Value intValue(Integer v) {
+        return JsonWithInt.Value.newBuilder().setIntegerValue(v).build();
+    }
+
+    private static JsonWithInt.Value longValue(Long v) {
+        return JsonWithInt.Value.newBuilder().setIntegerValue(v).build();
+    }
+
+    private static JsonWithInt.Value boolValue(Boolean v) {
+        return JsonWithInt.Value.newBuilder().setBoolValue(v).build();
+    }
+}