feat: 新增多用户支持、关系历史查询与恋爱决策建议功能

- 新增用户服务，支持多用户数据隔离与认证
- 新增关系历史查询接口，支持按冲突、积极、时间线等类型过滤
- 新增恋爱决策建议接口，基于图谱分析生成关系健康报告
- 优化前端图谱可视化，增加节点详情面板、图例和边标签显示
- 改进文本分析逻辑，支持实体去重和情感标注
- 新增完整流程测试脚本，验证分析、入库、查询全链路

OnceLove/oncelove-graphrag/api/src/services/user.service.js

@@ -0,0 +1,171 @@
+import { randomUUID } from 'crypto';
+
+/**
+ * 用户服务：管理用户 UUID 和认证
+ */
+export class UserService {
+  constructor(driver) {
+    this.driver = driver;
+  }
+
+  /**
+   * 创建或获取用户
+   */
+  async getOrCreateUser(token) {
+    const session = this.driver.session();
+    try {
+      // 尝试通过 token 查找用户
+      const result = await session.run(
+        `MATCH (u:User {token: $token}) RETURN u`,
+        { token }
+      );
+
+      if (result.records.length > 0) {
+        const user = result.records[0].get('u');
+        return {
+          id: user.properties.id,
+          token: user.properties.token,
+          createdAt: user.properties.created_at
+        };
+      }
+
+      // 创建新用户
+      const userId = randomUUID();
+      const createdAt = new Date().toISOString();
+      
+      await session.run(
+        `CREATE (u:User {id: $id, token: $token, created_at: $created_at})`,
+        { id: userId, token, created_at: createdAt }
+      );
+
+      return { id: userId, token, createdAt };
+    } finally {
+      await session.close();
+    }
+  }
+
+  /**
+   * 验证用户 token
+   */
+  async validateUser(token) {
+    if (!token) return null;
+    
+    const session = this.driver.session();
+    try {
+      const result = await session.run(
+        `MATCH (u:User {token: $token}) RETURN u`,
+        { token }
+      );
+
+      if (result.records.length > 0) {
+        const user = result.records[0].get('u');
+        return {
+          id: user.properties.id,
+          token: user.properties.token
+        };
+      }
+      return null;
+    } finally {
+      await session.close();
+    }
+  }
+
+  /**
+   * 获取用户图谱统计
+   */
+  async getUserGraphStats(userId) {
+    const session = this.driver.session();
+    try {
+      const result = await session.run(
+        `
+        MATCH (p:Person {user_id: $userId})
+        RETURN p.id AS id, p.name AS name, 'person' AS type, null AS occurred_at
+        LIMIT 200
+        `,
+        { userId }
+      );
+
+      const persons = result.records.map(r => ({
+        id: r.get('id'),
+        name: r.get('name'),
+        type: r.get('type'),
+        occurred_at: r.get('occurred_at')
+      }));
+
+      const events = await session.run(
+        `
+        MATCH (e:Event {user_id: $userId})
+        RETURN e.id AS id, e.summary AS name, 'event' AS type, e.occurred_at AS occurred_at
+        LIMIT 200
+        `,
+        { userId }
+      );
+
+      const topics = await session.run(
+        `
+        MATCH (t:Topic {user_id: $userId})
+        RETURN t.name AS id, t.name AS name, 'topic' AS type, null AS occurred_at
+        LIMIT 100
+        `,
+        { userId }
+      );
+
+      const nodes = [
+        ...persons,
+        ...events.records.map(r => ({
+          id: r.get('id'),
+          name: r.get('name'),
+          type: r.get('type'),
+          occurred_at: r.get('occurred_at')
+        })),
+        ...topics.records.map(r => ({
+          id: r.get('id'),
+          name: r.get('name'),
+          type: r.get('type'),
+          occurred_at: r.get('occurred_at')
+        }))
+      ];
+
+      // 查询关系
+      const personEventRels = await session.run(
+        `
+        MATCH (p:Person {user_id: $userId})-[:PARTICIPATES_IN]->(e:Event {user_id: $userId})
+        RETURN p.id AS source, e.id AS target, 'PARTICIPATES_IN' AS type
+        LIMIT 500
+        `,
+        { userId }
+      );
+
+      const eventTopicRels = await session.run(
+        `
+        MATCH (e:Event {user_id: $userId})-[:ABOUT]->(t:Topic {user_id: $userId})
+        RETURN e.id AS source, t.name AS target, 'ABOUT' AS type
+        LIMIT 300
+        `,
+        { userId }
+      );
+
+      const links = [
+        ...personEventRels.records.map(r => ({
+          source: r.get('source'),
+          target: r.get('target'),
+          type: r.get('type')
+        })),
+        ...eventTopicRels.records.map(r => ({
+          source: r.get('source'),
+          target: r.get('target'),
+          type: r.get('type')
+        }))
+      ];
+
+      return {
+        ok: true,
+        nodes,
+        links,
+        total: nodes.length
+      };
+    } finally {
+      await session.close();
+    }
+  }
+}