trabajando en el signup. problema con el mismo username aunque este delete at

src/main/java/com/imprimelibros/erp/login/LoginController.java

@@ -4,11 +4,26 @@ import java.util.Locale;
 
 import org.springframework.stereotype.Controller;
 import org.springframework.ui.Model;
+import org.springframework.validation.BindingResult;
 import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.ModelAttribute;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.servlet.mvc.support.RedirectAttributes;
+
+import com.imprimelibros.erp.login.dto.SignupForm;
+
+import jakarta.validation.Valid;
 
 @Controller
 public class LoginController {
 
+    private final SignupService signupService;
+
+    public LoginController(SignupService signupService) {
+        this.signupService = signupService;
+    }
+
     @GetMapping("/login")
     public String index(Model model, Locale locale) {
         model.addAttribute("form", "_login");
@@ -17,9 +32,44 @@ public class LoginController {
 
     @GetMapping("/signup")
     public String signup(Model model, Locale locale) {
+        if (!model.containsAttribute("signupForm")) {
+            model.addAttribute("signupForm", new SignupForm());
+        }
         model.addAttribute("form", "_signup");
         return "imprimelibros/login/login";
     }
 
+    @PostMapping("/signup")
+    public String doSignup(@Valid @ModelAttribute("signupForm") SignupForm form,
+                           BindingResult br,
+                           RedirectAttributes ra,
+                           Locale locale) {
+        if (br.hasErrors()) {
+            ra.addFlashAttribute("org.springframework.validation.BindingResult.signupForm", br);
+            ra.addFlashAttribute("signupForm", form);
+            ra.addFlashAttribute("signup_error", "Revisa el formulario");
+            return "redirect:/signup";
+        }
+        try {
+            signupService.register(form, locale);
+            ra.addFlashAttribute("info", "Te hemos enviado un email para confirmar tu correo.");
+            return "redirect:/login";
+        } catch (IllegalArgumentException ex) {
+            ra.addFlashAttribute("signup_error", ex.getMessage());
+            ra.addFlashAttribute("signupForm", form);
+            return "redirect:/signup";
+        }
+    }
+
+    @GetMapping("/verify")
+    public String verify(@RequestParam("token") String token, RedirectAttributes ra) {
+        boolean ok = signupService.verify(token);
+        if (ok) {
+            ra.addFlashAttribute("info", "¡Cuenta verificada! Ya puedes iniciar sesión.");
+        } else {
+            ra.addFlashAttribute("danger", "Enlace inválido o caducado. Solicita uno nuevo.");
+        }
+        return "redirect:/login";
+    }
     
 }