feat(orgchart): Introduce standalone orgchart RP and shared link public API

This commit includes:
- Added SharedLink data model and Keto-bypassed public API for orgchart view
- Configured 'orgfront' as a new OAuth2 client in hydra
- Applied MH Dashboard premium beige theme to OrgChart
- Implemented user lookup fallback to company code

backend/internal/repository/user_repository.go

@@ -20,6 +20,8 @@ type UserRepository interface {
 	CountByTenant(ctx context.Context, tenantID string) (int64, error)
 	CountByTenantIDs(ctx context.Context, tenantIDs []string) (map[string]int64, error)
 	CountByCompanyCodes(ctx context.Context, codes []string) (map[string]int64, error)
+	FindByTenantIDs(ctx context.Context, tenantIDs []string) ([]domain.User, error)
+	FindByCompanyCodes(ctx context.Context, codes []string) ([]domain.User, error)
 	Delete(ctx context.Context, id string) error
 
 	// Multiple identifiers support
@@ -261,3 +263,15 @@ func (r *userRepository) FindTenantIDByLoginID(ctx context.Context, loginID stri
 	}
 	return record.TenantID, nil
 }
+
+func (r *userRepository) FindByTenantIDs(ctx context.Context, tenantIDs []string) ([]domain.User, error) {
+	var users []domain.User
+	err := r.db.WithContext(ctx).Where("tenant_id IN ?", tenantIDs).Find(&users).Error
+	return users, err
+}
+
+func (r *userRepository) FindByCompanyCodes(ctx context.Context, codes []string) ([]domain.User, error) {
+	var users []domain.User
+	err := r.db.WithContext(ctx).Where("company_code IN ?", codes).Find(&users).Error
+	return users, err
+}