feat: timer intervallo misura su ricetta + auto-logout per inattività

- Recipe: nuovo campo measurement_interval_minutes (migration 003) con UI nel recipe editor
- Auto-logout: impostazione di sistema configurabile da admin/settings, timer inattività JS
  con warning modale 60s prima del logout, tracking eventi utente throttled
- Navbar: aggiunto link "Impostazioni" per admin (desktop + mobile)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/frontend/flask_app/templates/maker/recipe_editor.html

@@ -231,6 +231,23 @@
                     rows="3"
                     placeholder="{{ _('Descrizione opzionale della ricetta...') }}"></textarea>
         </div>
+
+        <!-- Intervallo di misura -->
+        <div>
+          <label class="tmf-label" for="recipe-interval">
+            {{ _('Intervallo misura (minuti)') }}
+          </label>
+          <input id="recipe-interval"
+                 type="number"
+                 x-model.number="measurementIntervalMinutes"
+                 class="tmf-input"
+                 min="1"
+                 max="1440"
+                 placeholder="{{ _('Es. 30') }}">
+          <p class="text-xs text-[var(--text-muted)] mt-1">
+            {{ _('Timer cicalino per ricordare la misurazione periodica') }}
+          </p>
+        </div>
       </div>
     </div>
   </div>
@@ -466,6 +483,9 @@ function recipeEditor() {
     versions: {{ (recipe.versions if recipe and recipe.versions else [])|tojson }},
     currentVersion: {{ (recipe.current_version.version_number if recipe and recipe.current_version else 0)|tojson }},
 
+    // ---- Measurement interval ----
+    measurementIntervalMinutes: {{ (recipe.measurement_interval_minutes if recipe and recipe.measurement_interval_minutes else 'null')|tojson }},
+
     // ---- File upload (preview image) ----
     currentFilePath: {{ (recipe.image_path if recipe and recipe.image_path else '')|tojson }},
     uploadingFile: false,
@@ -487,6 +507,11 @@ function recipeEditor() {
         description: this.description.trim(),
       };
 
+      // Measurement interval
+      if (this.measurementIntervalMinutes) {
+        payload.measurement_interval_minutes = parseInt(this.measurementIntervalMinutes, 10);
+      }
+
       // Include image_path for preview thumbnail
       if (this.currentFilePath) {
         payload.image_path = this.currentFilePath;