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-member.entity.ts

@@ -6,39 +6,39 @@ import {
   ManyToOne,
   JoinColumn,
   Unique,
-} from 'typeorm';
-import { GroupMemberRole } from '../common/enums';
-import { User } from './user.entity';
-import { Group } from './group.entity';
+} from "typeorm";
+import { GroupMemberRole } from "../common/enums";
+import { User } from "./user.entity";
+import { Group } from "./group.entity";
 
-@Entity('group_members')
-@Unique(['groupId', 'userId'])
+@Entity("group_members")
+@Unique(["groupId", "userId"])
 export class GroupMember {
-  @PrimaryGeneratedColumn('uuid')
+  @PrimaryGeneratedColumn("uuid")
   id: string;
 
   @Column()
   groupId: string;
 
-  @ManyToOne(() => Group, (group) => group.members, { onDelete: 'CASCADE' })
-  @JoinColumn({ name: 'groupId' })
+  @ManyToOne(() => Group, (group) => group.members, { onDelete: "CASCADE" })
+  @JoinColumn({ name: "groupId" })
   group: Group;
 
   @Column()
   userId: string;
 
-  @ManyToOne(() => User, (user) => user.groupMembers, { onDelete: 'CASCADE' })
-  @JoinColumn({ name: 'userId' })
+  @ManyToOne(() => User, (user) => user.groupMembers, { onDelete: "CASCADE" })
+  @JoinColumn({ name: "userId" })
   user: User;
 
   @Column({
-    type: 'enum',
+    type: "enum",
     enum: GroupMemberRole,
     default: GroupMemberRole.MEMBER,
   })
   role: GroupMemberRole;
 
-  @Column({ type: 'varchar', nullable: true, length: 50, comment: '组内昵称' })
+  @Column({ type: "varchar", nullable: true, length: 50, comment: "组内昵称" })
   nickname: string;
 
   @Column({ default: true })