feat: pg引入

src/types/index.d.ts

@@ -1,10 +1,12 @@
 import type { Mongoose } from 'mongoose';
 import type { RedisClientType } from 'redis';
 import type { Agent } from 'http';
+import type { Pool } from 'pg';
 
 declare global {
   var mongodb: Mongoose | string | null;
   var redisClient: RedisClientType | null;
+  var pgClient: Pool | null;
   var generatingQA: boolean;
   var generatingAbstract: boolean;
   var generatingVector: boolean;