feat(ai-chat): 实现AI对话流式响应及会话管理功能

- 新增AiChatController，提供SSE流式对话、新建会话、获取会话列表、获取会话历史记录和删除会话接口
- 实现AiChatService及其Impl，支持多轮对话流式响应、RAG检索辅助回答、会话权限校验和消息持久化
- 定义AiChatMessage实体映射ai_chat_history表，存储对话消息及元信息
- 新增MyBatis映射文件AiChatHistoryMapper.xml，支持会话查询、消息查询和会话删除等数据库操作
- 添加ChatRequest、CreateSessionRequest、ChatSessionVO等数据传输对象，规范接口参数与返回
- 实现DocumentProcessor用于文档解析、切片、向量化及存储，支持异步处理文档以供知识检索
- 设计系统提示词模板，结合项目及检索文档内容构建上下文，提高AI回答准确性和专业性
- 增加错误处理和权限验证，确保用户只能访问及操作自己的会话
- 优化流式响应的SSE事件推送，支持开始、块数据、引用文档、错误和完成事件通知
- 实现Token估算方法，统计交流token数用于统计和性能监控

src/main/java/cn/yinlihupo/controller/ai/AiChatController.java

@@ -112,7 +112,6 @@ public class AiChatController {
             ChatSessionVO session = aiChatService.createSession(
                     userId,
                     request.getProjectId(),
-                    request.getTimelineNodeId(),
                     request.getFirstMessage(),
                     request.getSessionTitle()
             );

src/main/java/cn/yinlihupo/domain/dto/ChatRequest.java

@@ -18,11 +18,6 @@ public class ChatRequest {
      */
     private Long projectId;
 
-    /**
-     * 时间节点ID（可选，用于时间维度知识库）
-     */
-    private Long timelineNodeId;
-
     /**
      * 用户消息内容
      */

src/main/java/cn/yinlihupo/domain/dto/CreateSessionRequest.java

@@ -13,11 +13,6 @@ public class CreateSessionRequest {
      */
     private Long projectId;
 
-    /**
-     * 时间节点ID（可选）
-     */
-    private Long timelineNodeId;
-
     /**
      * 首条消息内容（用于生成会话标题）
      */

src/main/java/cn/yinlihupo/domain/entity/AiChatMessage.java

@@ -39,11 +39,6 @@ public class AiChatMessage {
      */
     private Long projectId;
 
-    /**
-     * 关联时间节点ID
-     */
-    private Long timelineNodeId;
-
     /**
      * 角色：user-用户, assistant-助手, system-系统
      */

src/main/java/cn/yinlihupo/domain/entity/AiDocument.java

@@ -29,11 +29,6 @@ public class AiDocument {
      */
     private Long projectId;
 
-    /**
-     * 关联时间节点ID
-     */
-    private Long timelineNodeId;
-
     /**
      * 关联知识库ID
      */

src/main/java/cn/yinlihupo/domain/entity/ProjectTimeline.java

@@ -1,96 +0,0 @@
-package cn.yinlihupo.domain.entity;
-
-import cn.yinlihupo.common.handler.JsonbTypeHandler;
-import com.baomidou.mybatisplus.annotation.*;
-import lombok.Data;
-
-import java.time.LocalDate;
-import java.time.LocalDateTime;
-import java.util.List;
-
-/**
- * 项目时间节点实体类
- * 对应数据库表: project_timeline
- */
-@Data
-@TableName("project_timeline")
-public class ProjectTimeline {
-
-    @TableId(type = IdType.ASSIGN_ID)
-    private Long id;
-
-    /**
-     * 项目ID
-     */
-    private Long projectId;
-
-    /**
-     * 节点名称
-     */
-    private String nodeName;
-
-    /**
-     * 节点类型: phase-阶段, milestone-里程碑, event-事件, checkpoint-检查点
-     */
-    private String nodeType;
-
-    /**
-     * 父节点ID
-     */
-    private Long parentId;
-
-    /**
-     * 计划日期
-     */
-    private LocalDate planDate;
-
-    /**
-     * 实际日期
-     */
-    private LocalDate actualDate;
-
-    /**
-     * 描述
-     */
-    private String description;
-
-    /**
-     * 状态: pending-待开始, in_progress-进行中, completed-已完成, delayed-延期
-     */
-    private String status;
-
-    /**
-     * 排序
-     */
-    private Integer sortOrder;
-
-    /**
-     * 知识库范围配置["report","file","risk","ticket"]
-     */
-    @TableField(typeHandler = JsonbTypeHandler.class)
-    private List<String> kbScope;
-
-    /**
-     * 扩展数据
-     */
-    @TableField(typeHandler = JsonbTypeHandler.class)
-    private Object extraData;
-
-    /**
-     * 创建时间
-     */
-    @TableField(fill = FieldFill.INSERT)
-    private LocalDateTime createTime;
-
-    /**
-     * 更新时间
-     */
-    @TableField(fill = FieldFill.INSERT_UPDATE)
-    private LocalDateTime updateTime;
-
-    /**
-     * 删除标记
-     */
-    @TableLogic
-    private Integer deleted;
-}

src/main/java/cn/yinlihupo/domain/vo/ChatSessionVO.java

@@ -30,16 +30,6 @@ public class ChatSessionVO {
      */
     private String projectName;
 
-    /**
-     * 时间节点ID
-     */
-    private Long timelineNodeId;
-
-    /**
-     * 时间节点名称
-     */
-    private String timelineNodeName;
-
     /**
      * 最后消息时间
      */

src/main/java/cn/yinlihupo/domain/vo/ProjectDetailVO.java

@@ -586,55 +586,4 @@ public class ProjectDetailVO {
          */
         private LocalDateTime discoverTime;
     }
-
-    /**
-     * 时间节点信息
-     */
-    @Data
-    public static class TimelineInfo {
-        /**
-         * 节点ID
-         */
-        private Long id;
-
-        /**
-         * 节点名称
-         */
-        private String nodeName;
-
-        /**
-         * 节点类型
-         */
-        private String nodeType;
-
-        /**
-         * 计划日期
-         */
-        private LocalDate planDate;
-
-        /**
-         * 实际日期
-         */
-        private LocalDate actualDate;
-
-        /**
-         * 描述
-         */
-        private String description;
-
-        /**
-         * 状态
-         */
-        private String status;
-
-        /**
-         * 排序
-         */
-        private Integer sortOrder;
-
-        /**
-         * 知识库范围
-         */
-        private List<String> kbScope;
-    }
 }

src/main/java/cn/yinlihupo/service/ai/AiChatService.java

@@ -26,13 +26,11 @@ public interface AiChatService {
      *
      * @param userId      用户ID
      * @param projectId   项目ID
-     * @param timelineNodeId 时间节点ID（可选）
      * @param firstMessage 首条消息（用于生成标题）
      * @param customTitle  自定义标题（可选）
      * @return 会话信息
      */
-    ChatSessionVO createSession(Long userId, Long projectId, Long timelineNodeId,
+    ChatSessionVO createSession(Long userId, Long projectId, String firstMessage, String customTitle);
-                                String firstMessage, String customTitle);
 
     /**
      * 获取用户会话列表

src/main/java/cn/yinlihupo/service/ai/impl/AiChatServiceImpl.java

@@ -75,7 +75,7 @@ public class AiChatServiceImpl implements AiChatService {
             if (isNewSession) {
                 sessionId = UUID.randomUUID().toString();
                 String title = generateSessionTitle(request.getMessage());
-                createSession(userId, request.getProjectId(), request.getTimelineNodeId(), request.getMessage(), title);
+                createSession(userId, request.getProjectId(), request.getMessage(), title);
             } else {
                 // 验证会话权限
                 if (!hasSessionAccess(sessionId, userId)) {
@@ -93,8 +93,7 @@ public class AiChatServiceImpl implements AiChatService {
             ));
 
             // 2. 保存用户消息
-            saveMessage(finalSessionId, userId, request.getProjectId(),
+            saveMessage(finalSessionId, userId, request.getProjectId(), "user", request.getMessage(), null);
-                    request.getTimelineNodeId(), "user", request.getMessage(), null);
 
             // 3. RAG检索
             List<Document> retrievedDocs = performRetrieval(request);
@@ -140,7 +139,7 @@ public class AiChatServiceImpl implements AiChatService {
                                 .filter(id -> !id.isEmpty())
                                 .toArray(String[]::new);
                         Long messageId = saveMessage(finalSessionId, userId, request.getProjectId(),
-                                request.getTimelineNodeId(), "assistant",
+                                "assistant",
                                 fullResponse.toString(), docIds);
 
                         // 发送完成消息
@@ -166,8 +165,7 @@ public class AiChatServiceImpl implements AiChatService {
     }
 
     @Override
-    public ChatSessionVO createSession(Long userId, Long projectId, Long timelineNodeId,
+    public ChatSessionVO createSession(Long userId, Long projectId, String firstMessage, String customTitle) {
-                                       String firstMessage, String customTitle) {
         UUID sessionId = UUID.randomUUID();
         String sessionIdStr = sessionId.toString();
         String title = customTitle;
@@ -182,7 +180,6 @@ public class AiChatServiceImpl implements AiChatService {
         message.setSessionTitle(title);
         message.setUserId(userId);
         message.setProjectId(projectId);
-        message.setTimelineNodeId(timelineNodeId);
         message.setRole("system");
         message.setContent("会话创建");
         message.setMessageIndex(0);
@@ -200,7 +197,6 @@ public class AiChatServiceImpl implements AiChatService {
             vo.setProjectName(project.getProjectName());
         }
 
-        vo.setTimelineNodeId(timelineNodeId);
         vo.setMessageCount(1);
         vo.setCreateTime(LocalDateTime.now());
 
@@ -258,15 +254,6 @@ public class AiChatServiceImpl implements AiChatService {
         if (!Boolean.TRUE.equals(request.getUseRag()) && !Boolean.TRUE.equals(request.getUseTextToSql())) {
             return Collections.emptyList();
         }
-
-        if (request.getTimelineNodeId() != null) {
-            return ragRetriever.vectorSearchWithTimeline(
-                    request.getMessage(),
-                    request.getProjectId(),
-                    request.getTimelineNodeId(),
-                    5
-            );
-        } else {
         return ragRetriever.hybridSearch(
                 request.getMessage(),
                 request.getProjectId(),
@@ -275,7 +262,6 @@ public class AiChatServiceImpl implements AiChatService {
                 5
         );
     }
-    }
 
     /**
      * 构建系统Prompt
@@ -338,8 +324,7 @@ public class AiChatServiceImpl implements AiChatService {
      * 保存消息
      */
     private Long saveMessage(String sessionId, Long userId, Long projectId,
-                             Long timelineNodeId, String role, String content,
+                             String role, String content, String[] referencedDocIds) {
-                             String[] referencedDocIds) {
         // 获取当前最大序号
         Integer maxIndex = chatHistoryMapper.selectMaxMessageIndex(sessionId);
         int nextIndex = (maxIndex != null ? maxIndex : 0) + 1;
@@ -348,7 +333,6 @@ public class AiChatServiceImpl implements AiChatService {
         message.setSessionId(sessionId);
         message.setUserId(userId);
         message.setProjectId(projectId);
-        message.setTimelineNodeId(timelineNodeId);
         message.setRole(role);
         message.setContent(content);
         message.setReferencedDocIds(referencedDocIds);

src/main/java/cn/yinlihupo/service/ai/rag/DocumentProcessor.java

@@ -183,7 +183,6 @@ public class DocumentProcessor {
             Map<String, Object> metadata = new HashMap<>();
             // 项目关联属性（用于检索过滤）
             metadata.put("project_id", doc.getProjectId() != null ? doc.getProjectId().toString() : "");
-            metadata.put("timeline_node_id", doc.getTimelineNodeId() != null ? doc.getTimelineNodeId().toString() : "");
             metadata.put("kb_id", doc.getKbId() != null ? doc.getKbId().toString() : "");
             // 文档来源信息
             metadata.put("source_type", doc.getSourceType() != null ? doc.getSourceType() : "");

src/main/java/cn/yinlihupo/service/ai/rag/RagRetriever.java

@@ -57,37 +57,6 @@ public class RagRetriever {
         }
     }
 
-    /**
-     * 向量检索（带时间节点过滤）
-     *
-     * @param query          查询文本
-     * @param projectId      项目ID
-     * @param timelineNodeId 时间节点ID
-     * @param topK           返回数量
-     * @return 文档列表
-     */
-    public List<Document> vectorSearchWithTimeline(String query, Long projectId,
-                                                    Long timelineNodeId, int topK) {
-        try {
-            // project_id 和 timeline_node_id 在 metadata 中是字符串类型
-            SearchRequest searchRequest = SearchRequest.builder()
-                    .query(query)
-                    .topK(topK)
-                    .filterExpression("project_id == '" + projectId +
-                            "' && timeline_node_id == '" + timelineNodeId +
-                            "' && status == 'active'")
-                    .build();
-
-            List<Document> results = vectorStore.similaritySearch(searchRequest);
-            log.debug("向量检索完成（时间维度），项目ID: {}, 节点ID: {}, 结果数: {}",
-                    projectId, timelineNodeId, results.size());
-            return results;
-        } catch (Exception e) {
-            log.error("向量检索失败: {}", e.getMessage(), e);
-            return Collections.emptyList();
-        }
-    }
-
     /**
      * TextToSQL检索
      *

src/main/resources/mapper/AiChatHistoryMapper.xml

@@ -9,19 +9,16 @@
             MAX(ach.session_title) as sessionTitle,
             ach.project_id as projectId,
             p.project_name as projectName,
-            MAX(ach.timeline_node_id) as timelineNodeId,
-            pt.node_name as timelineNodeName,
             MAX(ach.create_time) as lastMessageTime,
             COUNT(*) as messageCount,
             MIN(ach.create_time) as createTime
         FROM ai_chat_history ach
         LEFT JOIN project p ON ach.project_id = p.id AND p.deleted = 0
-        LEFT JOIN project_timeline pt ON ach.timeline_node_id = pt.id AND pt.deleted = 0
         WHERE ach.user_id = #{userId}
         <if test="projectId != null">
             AND ach.project_id = #{projectId}
         </if>
-        GROUP BY ach.session_id, ach.project_id, p.project_name, pt.node_name
+        GROUP BY ach.session_id, ach.project_id, p.project_name
         ORDER BY lastMessageTime DESC
     </select>