feat(verification): add user identity verification system

Add comprehensive user verification feature including:
- VerificationGuideScreen: Guide screen explaining the verification process
- VerificationFormScreen: Form for submitting verification applications
- VerificationSettingsScreen: Settings page to view verification status
- verificationService: API service for verification operations
- verificationStore: State management for verification state
- DTOs: Types for verification records, status, and admin operations

The system supports multiple identity types (student, teacher, staff, alumni, external)
and includes both user-facing and admin-facing functionality.

src/types/dto.ts

@@ -773,7 +773,80 @@ export function extractTextFromSegments(segments?: MessageSegment[]): string {
   return result.trim();
 }
 
-// ==================== Vote DTOs ====================
+// ==================== Verification DTOs ====================
+
+// 用户身份类型
+export type UserIdentity = 'general' | 'student' | 'teacher' | 'staff' | 'alumni' | 'external';
+
+// 认证状态
+export type VerificationStatus = 'not_submitted' | 'pending' | 'approved' | 'rejected';
+
+// 认证记录
+export interface VerificationRecordDTO {
+  id: string;
+  user_id: string;
+  identity: UserIdentity;
+  status: VerificationStatus;
+  real_name: string;
+  student_id?: string;
+  employee_id?: string;
+  department?: string;
+  proof_materials: string;
+  reviewed_at?: string;
+  reviewed_by?: string;
+  reject_reason?: string;
+  created_at: string;
+  updated_at: string;
+}
+
+// 认证状态响应
+export interface VerificationStatusDTO {
+  identity: UserIdentity;
+  verification_status: VerificationStatus;
+  has_pending_request: boolean;
+  latest_record?: VerificationRecordDTO;
+}
+
+// 提交认证请求
+export interface SubmitVerificationRequest {
+  identity: UserIdentity;
+  real_name: string;
+  student_id?: string;
+  employee_id?: string;
+  department?: string;
+  proof_materials: string;
+}
+
+// 管理端认证列表项
+export interface AdminVerificationListItemDTO {
+  id: string;
+  user_id: string;
+  username: string;
+  nickname: string;
+  avatar: string;
+  identity: UserIdentity;
+  status: VerificationStatus;
+  real_name: string;
+  student_id?: string;
+  employee_id?: string;
+  department?: string;
+  created_at: string;
+  reviewed_at?: string;
+  reviewer_name?: string;
+}
+
+// 管理端认证详情
+export interface AdminVerificationDetailDTO extends AdminVerificationListItemDTO {
+  proof_materials: string;
+  reviewed_by?: string;
+  reject_reason?: string;
+}
+
+// 审核认证请求
+export interface ReviewVerificationRequest {
+  approve: boolean;
+  reject_reason?: string;
+}
 
 // 投票选项
 export interface VoteOptionDTO {