feat(measure): timer cicalino con countdown e buzzer dopo fine ciclo misura

- Blueprint: passa measurement_interval_minutes dalla ricetta al template task_execute
- Dopo "Fine ciclo misura": countdown MM:SS con banner amber animato sopra footer
- Allo scadere: 3 beep sonori (Web Audio API 880Hz) + reset misurazioni per nuovo ciclo
- Contatore cicli visibile nel banner timer

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

src/frontend/flask_app/blueprints/measure.py

@@ -135,11 +135,15 @@ def task_execute(task_id: int):
     # Load all task IDs for this recipe (ordered) for auto-advance
     recipe_id = task_resp.get("recipe_id")
     all_task_ids = []
+    measurement_interval_minutes = None
     if recipe_id:
         tasks_resp = api_client.get(f"/api/recipes/{recipe_id}/tasks")
         if isinstance(tasks_resp, list):
             sorted_tasks = sorted(tasks_resp, key=lambda t: t.get("order_index", 0))
             all_task_ids = [t["id"] for t in sorted_tasks]
+        recipe_resp = api_client.get(f"/api/recipes/{recipe_id}")
+        if not recipe_resp.get("error"):
+            measurement_interval_minutes = recipe_resp.get("measurement_interval_minutes")
 
     return render_template(
         "measure/task_execute.html",
@@ -147,6 +151,7 @@ def task_execute(task_id: int):
         lot_number=lot_number,
         serial_number=serial_number,
         all_task_ids=all_task_ids,
+        measurement_interval_minutes=measurement_interval_minutes,
     )