fix(ui): toggle password en login + fondo blanco card talento

Fix A: botón inline con ícono SVG (ojo/ojo tachado) en el campo
password de /login, alterna type password/text, aria-label según
estado. Sin librería nueva.
Fix B: .db-widget-star pierde el gradiente, hereda background blanco
de .db-widget igual que los demás cards. Borde y título teal intactos.

app/login/page.tsx

@@ -7,6 +7,7 @@ import { useRouter } from 'next/navigation'
 export default function LoginPage() {
   const [isPending, setIsPending] = useState(false)
   const [error, setError] = useState<string | null>(null)
+  const [showPassword, setShowPassword] = useState(false)
   const router = useRouter()
 
   const supabase = createBrowserClient(
@@ -54,15 +55,36 @@ export default function LoginPage() {
           </div>
           <div className="login-field">
             <label htmlFor="password" className="login-label">Contraseña</label>
-            <input
-              id="password"
-              name="password"
-              type="password"
-              autoComplete="current-password"
-              required
-              disabled={isPending}
-              className="text-short-input"
-            />
+            <div className="login-password-wrapper">
+              <input
+                id="password"
+                name="password"
+                type={showPassword ? 'text' : 'password'}
+                autoComplete="current-password"
+                required
+                disabled={isPending}
+                className="text-short-input"
+              />
+              <button
+                type="button"
+                className="login-password-toggle"
+                onClick={() => setShowPassword((v) => !v)}
+                aria-label={showPassword ? 'Ocultar contraseña' : 'Mostrar contraseña'}
+              >
+                {showPassword ? (
+                  <svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round" aria-hidden="true">
+                    <path d="M2 12s3.5-7 10-7 10 7 10 7-3.5 7-10 7-10-7-10-7Z" />
+                    <circle cx="12" cy="12" r="3" />
+                  </svg>
+                ) : (
+                  <svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round" aria-hidden="true">
+                    <path d="M2 12s3.5-7 10-7 10 7 10 7-3.5 7-10 7-10-7-10-7Z" />
+                    <circle cx="12" cy="12" r="3" />
+                    <path d="M3 3l18 18" />
+                  </svg>
+                )}
+              </button>
+            </div>
           </div>
           {error && (
             <p role="alert" className="field-error login-error">{error}</p>