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.

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)