refactor: migrate signup functionality to single usersignup module

backend/internal/usersignup/module.go

@@ -0,0 +1,60 @@
+package usersignup
+
+import (
+	"context"
+
+	"github.com/gin-gonic/gin"
+	"gorm.io/gorm"
+
+	"github.com/pocket-id/pocket-id/backend/internal/dto"
+	"github.com/pocket-id/pocket-id/backend/internal/model"
+)
+
+type TokenService interface {
+	GenerateAccessToken(user model.User, authenticationMethod string) (string, error)
+}
+
+type AuditLogger interface {
+	Create(ctx context.Context, event model.AuditLogEvent, ipAddress, userAgent, userID string, data model.AuditLogData, tx *gorm.DB) (model.AuditLog, bool)
+}
+
+type AppConfigProvider interface {
+	GetDbConfig() *model.AppConfig
+}
+
+type UserCreator interface {
+	CreateUserInternal(ctx context.Context, input dto.UserCreateDto, isLdapSync bool, tx *gorm.DB) (model.User, error)
+}
+
+type Dependencies struct {
+	DB *gorm.DB
+
+	Signer      TokenService
+	AuditLog    AuditLogger
+	AppConfig   AppConfigProvider
+	UserCreator UserCreator
+}
+
+type Module struct {
+	service *Service
+	handler *handler
+}
+
+func New(deps Dependencies) *Module {
+	service := newService(deps)
+	return &Module{
+		service: service,
+		handler: newHandler(service, deps.AppConfig),
+	}
+}
+
+// RegisterRoutes mounts the signup and signup-token management endpoints
+// adminAuth guards the admin token-management routes; signupRateLimit throttles public self-signup
+func (m *Module) RegisterRoutes(apiGroup *gin.RouterGroup, adminAuth, signupRateLimit gin.HandlerFunc) {
+	apiGroup.POST("/signup-tokens", adminAuth, m.handler.createSignupToken)
+	apiGroup.GET("/signup-tokens", adminAuth, m.handler.listSignupTokens)
+	apiGroup.DELETE("/signup-tokens/:id", adminAuth, m.handler.deleteSignupToken)
+	apiGroup.POST("/signup", signupRateLimit, m.handler.signup)
+	apiGroup.GET("/signup/setup", m.handler.checkInitialAdminSetupAvailable)
+	apiGroup.POST("/signup/setup", m.handler.signUpInitialAdmin)
+}