chore: 代码风格统一和项目文档添加

主要变更：

1. 代码风格统一
   - 统一使用双引号替代单引号
   - 保持项目代码风格一致性
   - 涵盖所有模块、配置、实体和服务文件

2. 项目文档
   - 新增 SECURITY_FIXES_SUMMARY.md - 安全修复总结文档
   - 新增 项目问题评估报告.md - 项目问题评估文档

3. 包含修改的文件类别
   - 配置文件：app, database, jwt, redis, cache, performance
   - 实体文件：所有 TypeORM 实体
   - 模块文件：所有业务模块
   - 公共模块：guards, decorators, interceptors, filters, utils
   - 测试文件：单元测试和 E2E 测试

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/entities/group.entity.ts

@@ -7,49 +7,49 @@ import {
   ManyToOne,
   JoinColumn,
   OneToMany,
-} from 'typeorm';
-import { User } from './user.entity';
-import { GroupMember } from './group-member.entity';
-import { Appointment } from './appointment.entity';
+} from "typeorm";
+import { User } from "./user.entity";
+import { GroupMember } from "./group-member.entity";
+import { Appointment } from "./appointment.entity";
 
-@Entity('groups')
+@Entity("groups")
 export class Group {
-  @PrimaryGeneratedColumn('uuid')
+  @PrimaryGeneratedColumn("uuid")
   id: string;
 
   @Column({ length: 100 })
   name: string;
 
-  @Column({ type: 'text', nullable: true })
+  @Column({ type: "text", nullable: true })
   description: string;
 
-  @Column({ type: 'varchar', nullable: true, length: 255 })
+  @Column({ type: "varchar", nullable: true, length: 255 })
   avatar: string;
 
   @Column()
   ownerId: string;
 
   @ManyToOne(() => User)
-  @JoinColumn({ name: 'ownerId' })
+  @JoinColumn({ name: "ownerId" })
   owner: User;
 
-  @Column({ default: 'normal', length: 20, comment: '类型: normal/guild' })
+  @Column({ default: "normal", length: 20, comment: "类型: normal/guild" })
   type: string;
 
-  @Column({ nullable: true, comment: '父组ID，用于子组' })
+  @Column({ nullable: true, comment: "父组ID，用于子组" })
   parentId: string;
 
   @ManyToOne(() => Group, { nullable: true })
-  @JoinColumn({ name: 'parentId' })
+  @JoinColumn({ name: "parentId" })
   parent: Group;
 
-  @Column({ type: 'text', nullable: true, comment: '公示信息' })
+  @Column({ type: "text", nullable: true, comment: "公示信息" })
   announcement: string;
 
-  @Column({ default: 50, comment: '最大成员数' })
+  @Column({ default: 50, comment: "最大成员数" })
   maxMembers: number;
 
-  @Column({ default: 1, comment: '当前成员数' })
+  @Column({ default: 1, comment: "当前成员数" })
   currentMembers: number;
 
   @Column({ default: true })