refactor(server): 收敛类型边界工具,aislop AI Slop 10 → 1

- 新增 common/buffer.ts bufferToArrayBuffer:9 处
  'as unknown as ArrayBuffer' 收敛为精确切片(含 byteOffset),
  消除潜在 Buffer 池偏移隐患,类型断言集中到单一实现
- 新增 common/stringify.ts:4 处重复的 stringify 助手收敛为共享实现
- aislop: AI Slop 10→1(仅剩 1 处有理由的 stringify 薄包装,
  eslint no-base-to-string 绕过所需);Code Quality 剩余
  4 重复块(声明式 SQL 配置)+ 2 文件过大(既有规模)均保留
- 测试 142 套件/1065 用例通过

apps/server/src/integration/config/integration-config.service.ts

@@ -1,3 +1,4 @@
+import { stringify } from '../../common/stringify';
 import { Injectable, Logger, BadRequestException, NotFoundException } from '@nestjs/common';
 import { InjectRepository } from '@nestjs/typeorm';
 import { Repository } from 'typeorm';
@@ -29,10 +30,6 @@ export class IntegrationConfigService {
   ) {}
 
   /** String() 包装：避免 unknown 收窄后触发 no-base-to-string。 */
-  private stringify(value: unknown): string {
-    return String(value);
-  }
-
   /** 解析 content JSON 并取 config 段（无 config 时回退整个对象）。 */
   private parseStoredConfig(content: string): Record<string, unknown> {
     const parsed = JSON.parse(content) as StoredConfigShape;
@@ -208,8 +205,8 @@ export class IntegrationConfigService {
   ): Promise<string | null> {
     try {
       if (type.toUpperCase() === 'DINGTALK') {
-        const appKey = this.stringify(config.agentId || '');
-        const appSecret = this.stringify(config.appSecret || '');
+        const appKey = stringify(config.agentId || '');
+        const appSecret = stringify(config.appSecret || '');
         if (!appKey || !appSecret) return null;
         return await this.fetchDingTalkToken(appKey, appSecret);
       }