feat(verification): add user identity verification system

Implement a complete user identity verification system with support for multiple identity types (student, teacher, staff, alumni). The system includes user-facing verification submission and status checking endpoints, admin endpoints for reviewing verification requests, middleware for protecting verification-required routes, and integration with the user model to track verification status.

internal/repository/verification_repo.go

@@ -0,0 +1,106 @@
+package repository
+
+import (
+	"carrot_bbs/internal/model"
+
+	"gorm.io/gorm"
+)
+
+type VerificationRepository interface {
+	Create(record *model.VerificationRecord) error
+	GetByID(id string) (*model.VerificationRecord, error)
+	GetLatestByUserID(userID string) (*model.VerificationRecord, error)
+	GetPendingByUserID(userID string) (*model.VerificationRecord, error)
+	List(page, pageSize int, status, keyword string) ([]*model.VerificationRecord, int64, error)
+	Update(record *model.VerificationRecord) error
+	GetRecordsByUserID(userID string, page, pageSize int) ([]*model.VerificationRecord, int64, error)
+}
+
+type verificationRepository struct {
+	db *gorm.DB
+}
+
+func NewVerificationRepository(db *gorm.DB) VerificationRepository {
+	return &verificationRepository{db: db}
+}
+
+func (r *verificationRepository) Create(record *model.VerificationRecord) error {
+	return r.db.Create(record).Error
+}
+
+func (r *verificationRepository) GetByID(id string) (*model.VerificationRecord, error) {
+	var record model.VerificationRecord
+	err := r.db.First(&record, "id = ?", id).Error
+	if err != nil {
+		return nil, err
+	}
+	return &record, nil
+}
+
+func (r *verificationRepository) GetLatestByUserID(userID string) (*model.VerificationRecord, error) {
+	var record model.VerificationRecord
+	err := r.db.Where("user_id = ?", userID).
+		Order("created_at DESC").
+		First(&record).Error
+	if err != nil {
+		return nil, err
+	}
+	return &record, nil
+}
+
+func (r *verificationRepository) GetPendingByUserID(userID string) (*model.VerificationRecord, error) {
+	var record model.VerificationRecord
+	err := r.db.Where("user_id = ? AND status = ?", userID, model.VerificationStatusPending).
+		First(&record).Error
+	if err != nil {
+		return nil, err
+	}
+	return &record, nil
+}
+
+func (r *verificationRepository) List(page, pageSize int, status, keyword string) ([]*model.VerificationRecord, int64, error) {
+	var records []*model.VerificationRecord
+	var total int64
+
+	query := r.db.Model(&model.VerificationRecord{})
+
+	if status != "" {
+		query = query.Where("verification_records.status = ?", status)
+	}
+
+	if keyword != "" {
+		query = query.Joins("JOIN users ON users.id = verification_records.user_id").
+			Where("users.username LIKE ? OR users.nickname LIKE ? OR verification_records.real_name LIKE ?",
+				"%"+keyword+"%", "%"+keyword+"%", "%"+keyword+"%")
+	}
+
+	query.Count(&total)
+
+	offset := (page - 1) * pageSize
+	err := query.Order("created_at DESC").
+		Offset(offset).
+		Limit(pageSize).
+		Find(&records).Error
+
+	return records, total, err
+}
+
+func (r *verificationRepository) Update(record *model.VerificationRecord) error {
+	return r.db.Save(record).Error
+}
+
+func (r *verificationRepository) GetRecordsByUserID(userID string, page, pageSize int) ([]*model.VerificationRecord, int64, error) {
+	var records []*model.VerificationRecord
+	var total int64
+
+	query := r.db.Model(&model.VerificationRecord{}).Where("user_id = ?", userID)
+	query.Count(&total)
+
+	offset := (page - 1) * pageSize
+	err := query.Order("created_at DESC").
+		Offset(offset).
+		Limit(pageSize).
+		Find(&records).Error
+
+	return records, total, err
+}