3c-fix: wrapper passes defaulted portions to core

completeCookingSession now forwards actualPortionsEaten and
leftoverEstimatePortions (after applying wrapper defaults) into
completeCookingSessionCore, so API callers omitting leftovers get
correct 100% deduction when mealBoxPortions is provided instead of
core's fallback to 0. Added regression test with leftovers omitted.

apps/api/src/lib/cooking.ts

@@ -97,7 +97,13 @@ export async function completeCookingSession(
     app,
     session,
     userId,
-    { ...input, portionsCooked: plannedPortions, mealBoxPortions },
+    {
+      ...input,
+      portionsCooked: plannedPortions,
+      mealBoxPortions,
+      actualPortionsEaten,
+      leftoverEstimatePortions,
+    },
     correlationId,
   );