feat: add Udemy courses and fix footer i18n + golangci-lint errors

- Add 5 Udemy courses with PDF certificate links (Go, Fyne, HTMX)
- Fix cv-footer.html to use CV data instead of hardcoded values
- Add i18n labels for footer (linkedin, github, domestika, email, phone)
- Fix 11 golangci-lint errors:
  - errcheck: proper Close() error handling in email/security/tests
  - staticcheck: simplify return and merge variable declaration
  - unused: remove legacy sendEmail and formatMessage functions

data/cv-en.json

@@ -736,6 +736,23 @@
       ],
       "courseID": "codecademy-certifications"
     },
+    {
+      "title": "Udemy Certifications",
+      "institution": "Udemy",
+      "courseLogo": "udemy.png",
+      "location": "Online",
+      "date": "2024-2025",
+      "duration": "Various",
+      "shortDescription": "Professional development courses in Go programming and modern web technologies through Udemy's comprehensive learning platform.",
+      "responsibilities": [
+        "<iconify-icon icon='simple-icons:go' width='60' height='60' class='default-company-icon' style='color: #00ADD8;'></iconify-icon><div><strong><a href='/static/pdf/udemy/Go - The Complete Guide.pdf' target='_blank'>Go - The Complete Guide</a></strong> <em>2024</em>: Comprehensive Go programming course covering fundamentals, concurrency, testing, and building production-ready applications</div>",
+        "<iconify-icon icon='simple-icons:go' width='60' height='60' class='default-company-icon' style='color: #00ADD8;'></iconify-icon><div><strong><a href='/static/pdf/udemy/Building a module in Go.pdf' target='_blank'>Building a Module in Go</a></strong> <em>2024</em>: Deep dive into Go modules, dependency management, versioning, and creating reusable packages</div>",
+        "<iconify-icon icon='simple-icons:go' width='60' height='60' class='default-company-icon' style='color: #00ADD8;'></iconify-icon><div><strong><a href='/static/pdf/udemy/Up and Running with Concurrency in Go.pdf' target='_blank'>Up and Running with Concurrency in Go</a></strong> <em>2024</em>: Advanced Go concurrency patterns including goroutines, channels, mutexes, and building concurrent applications</div>",
+        "<iconify-icon icon='simple-icons:go' width='60' height='60' class='default-company-icon' style='color: #00ADD8;'></iconify-icon><div><strong><a href='/static/pdf/udemy/Building GUI Applications with Fyne and Go.pdf' target='_blank'>Building GUI Applications with Fyne and Go</a></strong> <em>2024</em>: Desktop application development using the Fyne toolkit, creating cross-platform GUI applications with Go</div>",
+        "<iconify-icon icon='simple-icons:htmx' width='60' height='60' class='default-company-icon' style='color: #3366CC;'></iconify-icon><div><strong><a href='/static/pdf/udemy/HTMX - The Practical Guide.pdf' target='_blank'>HTMX - The Practical Guide</a></strong> <em>2024</em>: Modern web development with HTMX, building dynamic web applications with minimal JavaScript using hypermedia patterns</div>"
+      ],
+      "courseID": "udemy-certifications"
+    },
     {
       "title": "LinkedIn Learning Certifications",
       "institution": "LinkedIn Learning",

data/cv-es.json

@@ -741,6 +741,23 @@
       ],
       "courseID": "certificaciones-codecademy"
     },
+    {
+      "title": "Certificaciones Udemy",
+      "institution": "Udemy",
+      "courseLogo": "udemy.png",
+      "location": "Online",
+      "date": "2024-2025",
+      "duration": "Varios",
+      "shortDescription": "Cursos de desarrollo profesional en programación Go y tecnologías web modernas a través de la plataforma de aprendizaje integral de Udemy.",
+      "responsibilities": [
+        "<iconify-icon icon='simple-icons:go' width='60' height='60' class='default-company-icon' style='color: #00ADD8;'></iconify-icon><div><strong><a href='/static/pdf/udemy/Go - The Complete Guide.pdf' target='_blank'>Go - The Complete Guide</a></strong> <em>2024</em>: Curso completo de programación Go cubriendo fundamentos, concurrencia, testing y construcción de aplicaciones listas para producción</div>",
+        "<iconify-icon icon='simple-icons:go' width='60' height='60' class='default-company-icon' style='color: #00ADD8;'></iconify-icon><div><strong><a href='/static/pdf/udemy/Building a module in Go.pdf' target='_blank'>Building a Module in Go</a></strong> <em>2024</em>: Profundización en módulos Go, gestión de dependencias, versionado y creación de paquetes reutilizables</div>",
+        "<iconify-icon icon='simple-icons:go' width='60' height='60' class='default-company-icon' style='color: #00ADD8;'></iconify-icon><div><strong><a href='/static/pdf/udemy/Up and Running with Concurrency in Go.pdf' target='_blank'>Up and Running with Concurrency in Go</a></strong> <em>2024</em>: Patrones avanzados de concurrencia en Go incluyendo goroutines, channels, mutexes y construcción de aplicaciones concurrentes</div>",
+        "<iconify-icon icon='simple-icons:go' width='60' height='60' class='default-company-icon' style='color: #00ADD8;'></iconify-icon><div><strong><a href='/static/pdf/udemy/Building GUI Applications with Fyne and Go.pdf' target='_blank'>Building GUI Applications with Fyne and Go</a></strong> <em>2024</em>: Desarrollo de aplicaciones de escritorio usando el toolkit Fyne, creando aplicaciones GUI multiplataforma con Go</div>",
+        "<iconify-icon icon='simple-icons:htmx' width='60' height='60' class='default-company-icon' style='color: #3366CC;'></iconify-icon><div><strong><a href='/static/pdf/udemy/HTMX - The Practical Guide.pdf' target='_blank'>HTMX - The Practical Guide</a></strong> <em>2024</em>: Desarrollo web moderno con HTMX, construyendo aplicaciones web dinámicas con JavaScript mínimo usando patrones hypermedia</div>"
+      ],
+      "courseID": "certificaciones-udemy"
+    },
     {
       "title": "Certificaciones LinkedIn Learning",
       "institution": "LinkedIn Learning",

data/ui-en.json

@@ -36,7 +36,12 @@
   },
   "footer": {
     "viewOnGithub": "View this project on GitHub",
-    "lastUpdated": "Last updated"
+    "lastUpdated": "Last updated",
+    "linkedin": "linkedin_",
+    "github": "github_",
+    "domestika": "domestika_",
+    "email": "email@",
+    "phone": "phone#"
   },
   "portfolio": {
     "seeAllProjects": "See all projects on my",

data/ui-es.json

@@ -36,7 +36,12 @@
   },
   "footer": {
     "viewOnGithub": "Ver este proyecto en GitHub",
-    "lastUpdated": "Última actualización"
+    "lastUpdated": "Última actualización",
+    "linkedin": "linkedin_",
+    "github": "github_",
+    "domestika": "domestika_",
+    "email": "email@",
+    "phone": "teléfono#"
   },
   "portfolio": {
     "seeAllProjects": "Ver todos los proyectos en mi",

internal/handlers/cv_text.go

@@ -44,11 +44,7 @@ func isTextBrowser(r *http.Request) bool {
 
 	// Check Accept header - if client prefers text/plain
 	accept := r.Header.Get("Accept")
-	if strings.HasPrefix(accept, "text/plain") {
+	return strings.HasPrefix(accept, "text/plain")
-		return true
-	}
-
-	return false
 }
 
 // ==============================================================================
@@ -72,10 +68,7 @@ func (h *CVHandler) PlainText(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// Check icons parameter (default: true)
-	showIcons := true
+	showIcons := r.URL.Query().Get("icons") != "false"
-	if r.URL.Query().Get("icons") == "false" {
-		showIcons = false
-	}
 
 	// Prepare template data using shared helper (loads CV data)
 	data, err := h.prepareTemplateData(langCode)

internal/middleware/security_logger.go

@@ -132,7 +132,11 @@ func logToSecurityFile(eventJSON []byte) {
 		log.Printf("WARNING: Failed to open security log file: %v", err)
 		return
 	}
-	defer f.Close()
+	defer func() {
+		if err := f.Close(); err != nil {
+			log.Printf("WARNING: Failed to close security log file: %v", err)
+		}
+	}()
 
 	// Write event with newline
 	if _, err := f.Write(eventJSON); err != nil {

internal/models/ui/ui.go

@@ -102,6 +102,11 @@ type Sections struct {
 type Footer struct {
 	ViewOnGithub string `json:"viewOnGithub"`
 	LastUpdated  string `json:"lastUpdated"`
+	Linkedin     string `json:"linkedin"`
+	Github       string `json:"github"`
+	Domestika    string `json:"domestika"`
+	Email        string `json:"email"`
+	Phone        string `json:"phone"`
 }
 
 // Portfolio labels

internal/services/email.go

@@ -224,74 +224,7 @@ func (e *EmailService) sendMultipartEmail(subject, htmlBody, textBody, replyTo s
 	if err != nil {
 		return fmt.Errorf("failed to connect to SMTP server: %w", err)
 	}
-	defer client.Close()
+	defer func() { _ = client.Close() }()
-
-	// Authenticate
-	if err = client.Auth(auth); err != nil {
-		return fmt.Errorf("SMTP authentication failed: %w", err)
-	}
-
-	// Set sender and recipient
-	if err = client.Mail(from); err != nil {
-		return fmt.Errorf("failed to set sender: %w", err)
-	}
-	if err = client.Rcpt(to); err != nil {
-		return fmt.Errorf("failed to set recipient: %w", err)
-	}
-
-	// Send message
-	w, err := client.Data()
-	if err != nil {
-		return fmt.Errorf("failed to get data writer: %w", err)
-	}
-
-	_, err = w.Write([]byte(message))
-	if err != nil {
-		return fmt.Errorf("failed to write message: %w", err)
-	}
-
-	err = w.Close()
-	if err != nil {
-		return fmt.Errorf("failed to close writer: %w", err)
-	}
-
-	return client.Quit()
-}
-
-// sendEmail sends an email using SMTP (plain text only - legacy)
-func (e *EmailService) sendEmail(subject, body string) error {
-	// Validate config
-	if e.config.SMTPHost == "" || e.config.SMTPPort == "" {
-		return fmt.Errorf("SMTP configuration incomplete")
-	}
-	if e.config.SMTPUser == "" || e.config.SMTPPassword == "" {
-		return fmt.Errorf("SMTP credentials missing")
-	}
-	if e.config.ToEmail == "" {
-		return fmt.Errorf("recipient email not configured")
-	}
-
-	// Build email message
-	from := e.config.FromEmail
-	if from == "" {
-		from = e.config.SMTPUser
-	}
-
-	to := e.config.ToEmail
-	message := e.formatMessage(from, to, subject, body)
-
-	// SMTP server address
-	addr := fmt.Sprintf("%s:%s", e.config.SMTPHost, e.config.SMTPPort)
-
-	// Setup authentication
-	auth := smtp.PlainAuth("", e.config.SMTPUser, e.config.SMTPPassword, e.config.SMTPHost)
-
-	// Connect to SMTP server with TLS
-	client, err := e.connectSMTP(addr)
-	if err != nil {
-		return fmt.Errorf("failed to connect to SMTP server: %w", err)
-	}
-	defer client.Close()
 
 	// Authenticate
 	if err = client.Auth(auth); err != nil {
@@ -342,7 +275,7 @@ func (e *EmailService) connectSMTP(addr string) (*smtp.Client, error) {
 		}
 		client, err := smtp.NewClient(conn, e.config.SMTPHost)
 		if err != nil {
-			conn.Close()
+			_ = conn.Close()
 			return nil, fmt.Errorf("SMTP client creation failed: %w", err)
 		}
 		return client, nil
@@ -411,23 +344,3 @@ func (e *EmailService) formatMultipartMessage(from, to, replyTo, subject, htmlBo
 
 	return message.String()
 }
-
-// formatMessage formats an email message with proper headers (plain text only)
-func (e *EmailService) formatMessage(from, to, subject, body string) string {
-	headers := make(map[string]string)
-	headers["From"] = from
-	headers["To"] = to
-	headers["Subject"] = subject
-	headers["MIME-Version"] = "1.0"
-	headers["Content-Type"] = "text/plain; charset=\"utf-8\""
-	headers["Date"] = time.Now().Format(time.RFC1123Z)
-
-	var message strings.Builder
-	for k, v := range headers {
-		message.WriteString(fmt.Sprintf("%s: %s\r\n", k, v))
-	}
-	message.WriteString("\r\n")
-	message.WriteString(body)
-
-	return message.String()
-}

templates/partials/cv/cv-footer.html

@@ -5,38 +5,38 @@
     <div class="actual-content">
         <ul class="footer-content">
             <li>
-                <div class="footer-label">linkedin_</div>
+                <div class="footer-label">{{.UI.Footer.Linkedin}}</div>
                 <div class="footer-separator"><i class="fa fa-circle"></i></div>
                 <div class="footer-value">
                     <a href="{{.CV.Personal.LinkedIn}}" target="_blank" rel="noopener noreferrer">{{.CV.Personal.LinkedIn}}</a>
                 </div>
             </li>
             <li>
-                <div class="footer-label">github_</div>
+                <div class="footer-label">{{.UI.Footer.Github}}</div>
                 <div class="footer-separator"><i class="fa fa-circle"></i></div>
                 <div class="footer-value">
                     <a href="{{.CV.Personal.GitHub}}" target="_blank" rel="noopener noreferrer">{{.CV.Personal.GitHub}}</a>
                 </div>
             </li>
             <li>
-                <div class="footer-label">domestika_</div>
+                <div class="footer-label">{{.UI.Footer.Domestika}}</div>
                 <div class="footer-separator"><i class="fa fa-circle"></i></div>
                 <div class="footer-value">
                     <a href="{{.CV.Personal.Domestika}}" target="_blank" rel="noopener noreferrer">{{.CV.Personal.Domestika}}</a>
                 </div>
             </li>
             <li>
-                <div class="footer-label">email@</div>
+                <div class="footer-label">{{.UI.Footer.Email}}</div>
                 <div class="footer-separator"><i class="fa fa-circle"></i></div>
                 <div class="footer-value">
                     <a href="mailto:{{.CV.Personal.Email}}" target="_blank" rel="noopener noreferrer">{{.CV.Personal.Email}}</a>
                 </div>
             </li>
             <li>
-                <div class="footer-label">phone#</div>
+                <div class="footer-label">{{.UI.Footer.Phone}}</div>
                 <div class="footer-separator"><i class="fa fa-circle"></i></div>
                 <div class="footer-value">
-                    <a href="tel:+34676875420" target="_blank" rel="noopener noreferrer">+34 676 875 420</a>
+                    <a href="tel:{{.CV.Personal.Phone}}" target="_blank" rel="noopener noreferrer">{{.CV.Personal.Phone}}</a>
                 </div>
             </li>
         </ul>

tests/integration/email_test.go

@@ -39,7 +39,7 @@ func TestSMTPConnection(t *testing.T) {
 			if err != nil {
 				t.Fatalf("TLS dial failed: %v", err)
 			}
-			defer conn.Close()
+			defer func() { _ = conn.Close() }()
 			t.Log("TLS connection established (port 465 - implicit SSL)")
 		} else {
 			// STARTTLS
@@ -47,7 +47,7 @@ func TestSMTPConnection(t *testing.T) {
 			if err != nil {
 				t.Fatalf("SMTP dial failed: %v", err)
 			}
-			defer client.Close()
+			defer func() { _ = client.Close() }()
 
 			if err := client.StartTLS(tlsConfig); err != nil {
 				t.Fatalf("STARTTLS failed: %v", err)
@@ -71,7 +71,7 @@ func TestSMTPConnection(t *testing.T) {
 			if err != nil {
 				t.Fatalf("TLS dial failed: %v", err)
 			}
-			defer conn.Close()
+			defer func() { _ = conn.Close() }()
 
 			client, err = smtp.NewClient(conn, host)
 			if err != nil {
@@ -88,7 +88,7 @@ func TestSMTPConnection(t *testing.T) {
 				t.Fatalf("STARTTLS failed: %v", err)
 			}
 		}
-		defer client.Close()
+		defer func() { _ = client.Close() }()
 
 		auth := smtp.PlainAuth("", user, pass, host)
 		if err := client.Auth(auth); err != nil {