Add NoOp email service, /docs shortcut and fix streak timezone bug

Replace nil email service pattern with NoOpEmailService (Null Object)
to eliminate nil pointer panics across all handlers.

Add /docs route as a shortcut to Swagger UI.

Fix streak calculation returning 0 when server timezone differs from
UTC — CreatedAt was not converted to UTC before date extraction.

cmd/api/main.go

@@ -95,7 +95,7 @@ func main() {
 	jwtService := auth.NewJWTService(cfg.JWTSecret, jwtExpiryHours)
 	passwordHasher := crypto.NewBcryptHasher()
 
-	var emailService services.EmailService
+	var emailService services.EmailService = &services.NoOpEmailService{}
 	if cfg.SMTPHost != "" {
 		smtpPort, err := strconv.Atoi(cfg.SMTPPort)
 		if err != nil {

internal/application/commands/register_user.go

@@ -73,7 +73,7 @@ func (h *RegisterUserHandler) Handle(ctx context.Context, cmd RegisterUserComman
 	user := entities.NewUser(cmd.Email, hashedPassword)
 
 	emailVerificationRequired := false
-	if h.emailService != nil {
+	if h.emailService.IsEnabled() {
 		token, err := h.generateVerificationToken()
 		if err != nil {
 			return nil, fmt.Errorf("failed to generate verification token: %w", err)

internal/application/commands/register_user_test.go

@@ -2,6 +2,7 @@ package commands
 
 import (
 	"apocapoc-api/internal/domain/repositories"
+	"apocapoc-api/internal/domain/services"
 	"apocapoc-api/internal/shared/pagination"
 	"context"
 	"errors"
@@ -71,7 +72,7 @@ func TestRegisterUserHandler_Success(t *testing.T) {
 		},
 	}
 	hasher := &mockPasswordHasher{}
-	handler := NewRegisterUserHandler(repo, hasher, nil, "", "open", false)
+	handler := NewRegisterUserHandler(repo, hasher, &services.NoOpEmailService{}, "", "open", false)
 
 	cmd := RegisterUserCommand{
 		Email:    "test@example.com",
@@ -88,7 +89,7 @@ func TestRegisterUserHandler_Success(t *testing.T) {
 	}
 
 	if result.EmailVerificationRequired {
-		t.Error("expected email verification to not be required when emailService is nil")
+		t.Error("expected email verification to not be required when email is disabled")
 	}
 
 	if createdUser == nil {
@@ -103,7 +104,7 @@ func TestRegisterUserHandler_Success(t *testing.T) {
 func TestRegisterUserHandler_InvalidEmail(t *testing.T) {
 	repo := &mockUserRepo{}
 	hasher := &mockPasswordHasher{}
-	handler := NewRegisterUserHandler(repo, hasher, nil, "", "open", false)
+	handler := NewRegisterUserHandler(repo, hasher, &services.NoOpEmailService{}, "", "open", false)
 
 	tests := []struct {
 		name  string
@@ -135,7 +136,7 @@ func TestRegisterUserHandler_InvalidEmail(t *testing.T) {
 func TestRegisterUserHandler_InvalidPassword(t *testing.T) {
 	repo := &mockUserRepo{}
 	hasher := &mockPasswordHasher{}
-	handler := NewRegisterUserHandler(repo, hasher, nil, "", "open", false)
+	handler := NewRegisterUserHandler(repo, hasher, &services.NoOpEmailService{}, "", "open", false)
 
 	tests := []struct {
 		name     string
@@ -174,7 +175,7 @@ func TestRegisterUserHandler_EmailAlreadyExists(t *testing.T) {
 		},
 	}
 	hasher := &mockPasswordHasher{}
-	handler := NewRegisterUserHandler(repo, hasher, nil, "", "open", false)
+	handler := NewRegisterUserHandler(repo, hasher, &services.NoOpEmailService{}, "", "open", false)
 
 	cmd := RegisterUserCommand{
 		Email:    "test@example.com",
@@ -195,7 +196,7 @@ func TestRegisterUserHandler_PasswordHashingError(t *testing.T) {
 			return "", expectedErr
 		},
 	}
-	handler := NewRegisterUserHandler(repo, hasher, nil, "", "open", false)
+	handler := NewRegisterUserHandler(repo, hasher, &services.NoOpEmailService{}, "", "open", false)
 
 	cmd := RegisterUserCommand{
 		Email:    "test@example.com",
@@ -216,7 +217,7 @@ func TestRegisterUserHandler_RepositoryError(t *testing.T) {
 		},
 	}
 	hasher := &mockPasswordHasher{}
-	handler := NewRegisterUserHandler(repo, hasher, nil, "", "open", false)
+	handler := NewRegisterUserHandler(repo, hasher, &services.NoOpEmailService{}, "", "open", false)
 
 	cmd := RegisterUserCommand{
 		Email:    "test@example.com",
@@ -232,7 +233,7 @@ func TestRegisterUserHandler_RepositoryError(t *testing.T) {
 func TestRegisterUserHandler_EdgeCases(t *testing.T) {
 	repo := &mockUserRepo{}
 	hasher := &mockPasswordHasher{}
-	handler := NewRegisterUserHandler(repo, hasher, nil, "", "open", false)
+	handler := NewRegisterUserHandler(repo, hasher, &services.NoOpEmailService{}, "", "open", false)
 
 	tests := []struct {
 		name    string
@@ -285,7 +286,7 @@ func TestRegisterUserHandler_EdgeCases(t *testing.T) {
 func TestRegisterUserHandler_ClosedRegistration(t *testing.T) {
 	repo := &mockUserRepo{}
 	hasher := &mockPasswordHasher{}
-	handler := NewRegisterUserHandler(repo, hasher, nil, "", "closed", false)
+	handler := NewRegisterUserHandler(repo, hasher, &services.NoOpEmailService{}, "", "closed", false)
 
 	cmd := RegisterUserCommand{
 		Email:    "test@example.com",

internal/application/commands/request_password_reset_test.go

@@ -89,6 +89,10 @@ func (m *mockRequestResetEmailService) HealthCheck() error {
 	return nil
 }
 
+func (m *mockRequestResetEmailService) IsEnabled() bool {
+	return true
+}
+
 func TestRequestPasswordResetHandler_Success(t *testing.T) {
 	user := entities.NewUser("test@example.com", "hash")
 	user.ID = "user-123"

internal/application/commands/verify_email_test.go

@@ -69,6 +69,10 @@ func (m *mockEmailService) HealthCheck() error {
 	return nil
 }
 
+func (m *mockEmailService) IsEnabled() bool {
+	return true
+}
+
 func TestVerifyEmailHandler_Success(t *testing.T) {
 	token := "valid-token"
 	expiry := time.Now().Add(24 * time.Hour)

internal/domain/services/email_service.go

@@ -10,4 +10,11 @@ type EmailMessage struct {
 type EmailService interface {
 	Send(message EmailMessage) error
 	HealthCheck() error
+	IsEnabled() bool
 }
+
+type NoOpEmailService struct{}
+
+func (n *NoOpEmailService) Send(_ EmailMessage) error { return nil }
+func (n *NoOpEmailService) HealthCheck() error        { return nil }
+func (n *NoOpEmailService) IsEnabled() bool           { return false }

internal/domain/services/streak.go

@@ -49,7 +49,8 @@ func buildEntryMap(entries []*entities.HabitEntry) map[string]*entities.HabitEnt
 }
 
 func allScheduledDates(habit *entities.Habit, now time.Time) []time.Time {
-	start := time.Date(habit.CreatedAt.Year(), habit.CreatedAt.Month(), habit.CreatedAt.Day(), 0, 0, 0, 0, time.UTC)
+	createdUTC := habit.CreatedAt.UTC()
+	start := time.Date(createdUTC.Year(), createdUTC.Month(), createdUTC.Day(), 0, 0, 0, 0, time.UTC)
 	today := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, time.UTC)
 	freq := string(habit.Frequency)
 

internal/infrastructure/email/smtp_service.go

@@ -107,6 +107,10 @@ func (s *SMTPService) GetConfig() SMTPConfig {
 	return s.config
 }
 
+func (s *SMTPService) IsEnabled() bool {
+	return true
+}
+
 func (s *SMTPService) HealthCheck() error {
 	dialer := mail.NewDialer(s.config.Host, s.config.Port, s.config.Username, s.config.Password)
 	dialer.TLSConfig = &tls.Config{

internal/infrastructure/http/integration_test.go

@@ -11,6 +11,7 @@ import (
 
 	"apocapoc-api/internal/application/commands"
 	"apocapoc-api/internal/application/queries"
+	"apocapoc-api/internal/domain/services"
 	"apocapoc-api/internal/i18n"
 	"apocapoc-api/internal/infrastructure/auth"
 	"apocapoc-api/internal/infrastructure/crypto"
@@ -43,14 +44,15 @@ func setupTestServer(t *testing.T) *TestServer {
 	refreshTokenRepo := sqlite.NewRefreshTokenRepository(db)
 	passwordResetTokenRepo := sqlite.NewPasswordResetTokenRepository(db)
 
-	registerHandler := commands.NewRegisterUserHandler(userRepo, passwordHasher, nil, "", "open", false)
+	noOpEmail := &services.NoOpEmailService{}
+	registerHandler := commands.NewRegisterUserHandler(userRepo, passwordHasher, noOpEmail, "", "open", false)
 	loginHandler := queries.NewLoginUserHandler(userRepo, passwordHasher)
 	refreshTokenHandler := queries.NewRefreshTokenHandler(refreshTokenRepo, userRepo)
 	revokeTokenHandler := commands.NewRevokeTokenHandler(refreshTokenRepo)
 	revokeAllTokensHandler := commands.NewRevokeAllTokensHandler(refreshTokenRepo)
-	verifyEmailHandler := commands.NewVerifyEmailHandler(userRepo, nil, false)
+	verifyEmailHandler := commands.NewVerifyEmailHandler(userRepo, noOpEmail, false)
-	resendVerificationEmailHandler := commands.NewResendVerificationEmailHandler(userRepo, nil, "")
+	resendVerificationEmailHandler := commands.NewResendVerificationEmailHandler(userRepo, noOpEmail, "")
-	requestPasswordResetHandler := commands.NewRequestPasswordResetHandler(userRepo, passwordResetTokenRepo, nil, "")
+	requestPasswordResetHandler := commands.NewRequestPasswordResetHandler(userRepo, passwordResetTokenRepo, noOpEmail, "")
 	resetPasswordHandler := commands.NewResetPasswordHandler(userRepo, passwordResetTokenRepo, passwordHasher)
 	createHandler := commands.NewCreateHabitHandler(habitRepo)
 	getTodaysHandler := queries.NewGetTodaysHabitsHandler(habitRepo, entryRepo)

internal/infrastructure/http/router.go

@@ -30,6 +30,9 @@ func NewRouter(appURL string, habitHandlers *HabitHandlers, authHandlers *AuthHa
 		AllowCredentials: true,
 	}))
 
+	r.Get("/docs", httpSwagger.Handler(
+		httpSwagger.URL("/api/v1/docs/doc.json"),
+	))
 	r.Get("/api/v1/docs", func(w http.ResponseWriter, r *http.Request) {
 		http.Redirect(w, r, "/api/v1/docs/index.html", http.StatusMovedPermanently)
 	})