Monitor e quota registrata mostrano NaN invece di andare in errore (Refs #118)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019A9CSrh9rfM5WwqKtg8BSE

src/frontend/flask_app/templates/measure/task_execute.html

@@ -472,7 +472,8 @@
             <path stroke-linecap="round" stroke-linejoin="round" d="M5 13l4 4L19 7"/>
           </svg>
           <span>{{ _('Registrata') }}:</span>
-          <span class="font-mono font-bold" x-text="getMeasuredValue(currentSubtask?.id)?.toFixed(3) || '—'"></span>
+          {# #118: quota registrata senza valore (visione, NaN) #}
+          <span class="font-mono font-bold" x-text="getMeasuredValue(currentSubtask?.id)?.toFixed(3) ?? 'NaN'"></span>
           <span x-text="currentSubtask?.unit || 'mm'"></span>
         </div>
       </div>

src/frontend/flask_app/templates/monitor/index.html

@@ -56,7 +56,7 @@
               <span class="truncate" x-text="s.description"></span>
               <span class="font-mono whitespace-nowrap"
                     :class="s.in_tolerance ? 'text-green-700' : 'text-red-700 font-bold'"
-                    x-text="s.mean.toFixed(3) + ' ' + s.unit"></span>
+                    x-text="(s.mean == null ? 'NaN' : s.mean.toFixed(3)) + ' ' + s.unit"></span>{# #118: quota con soli valori NaN: media null #}
             </li>
           </template>
         </ul>