fix: check error return value in ExportPDF handler

- Add proper error handling for w.Write() call in ExportPDF function
- Fixes golangci-lint errcheck issue at cv.go:285
- Log error if response write fails

internal/handlers/cv.go

@@ -282,7 +282,9 @@ func (h *CVHandler) ExportPDF(w http.ResponseWriter, r *http.Request) {
 </body>
 </html>`, lang, message, lang, message, body, redirectMsg)
 
-	w.Write([]byte(html))
+	if _, err := w.Write([]byte(html)); err != nil {
+		log.Printf("Error writing response: %v", err)
+	}
 }
 
 // splitSkills splits skill categories between left (page 1) and right (page 2) sidebars