Statistiche sessioni: conteggio misure solo sui run della ricetta (#58)

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/backend/api/routers/statistics.py

@@ -257,17 +257,20 @@ async def get_recipe_runs(
     db: AsyncSession = Depends(get_db),
 ) -> list[dict]:
     """#58: production runs of a recipe (for the "Sessione" filter), newest first."""
-    # Misure per sessione in una sola query, poi unite alle sessioni.
-    counts = dict((await db.execute(
-        select(Measurement.production_run_id, func.count(Measurement.id))
-        .where(Measurement.production_run_id.is_not(None))
-        .group_by(Measurement.production_run_id)
-    )).all())
     runs = (await db.execute(
         select(ProductionRun)
         .where(ProductionRun.recipe_id == recipe_id)
         .order_by(ProductionRun.started_at.desc(), ProductionRun.id.desc())
     )).scalars().all()
+    # #58: conta solo le misure dei run della ricetta, non tutta la tabella.
+    run_ids = [r.id for r in runs]
+    counts = {}
+    if run_ids:
+        counts = dict((await db.execute(
+            select(Measurement.production_run_id, func.count(Measurement.id))
+            .where(Measurement.production_run_id.in_(run_ids))
+            .group_by(Measurement.production_run_id)
+        )).all())
     operator_ids = {r.operator_id for r in runs}
     names = {}
     if operator_ids: