fix(meals): round checkcomponents amounts half-up

Keep SQS deduction amounts on the same rounding path as submit_order so extra-precision totals cannot diverge by a cent.

functions/aggregate_orders/handler.py

@@ -5,7 +5,7 @@ import logging
 import os
 from collections import defaultdict
 from datetime import datetime
-from decimal import Decimal
+from decimal import Decimal, ROUND_HALF_UP
 from zoneinfo import ZoneInfo
 
 import boto3
@@ -101,7 +101,9 @@ def build_checkcomponents_payload(week: str, orders: list[dict]) -> dict:
         lines.append(
             {
                 "employee_email": email,
-                "amount": format(amount.quantize(Decimal("0.01")), "f"),
+                "amount": format(
+                    amount.quantize(Decimal("0.01"), rounding=ROUND_HALF_UP), "f"
+                ),
             }
         )
     week_token = week if str(week).upper().startswith("WEEK#") else f"WEEK#{week}"

tests/test_aggregate_orders.py

@@ -558,6 +558,20 @@ class TestCheckcomponentsPayload:
         )
         assert payload["week"] == "WEEK#2026-W20"
 
+    def test_rounds_amount_half_up(self, handler_module):
+        payload = handler_module.build_checkcomponents_payload(
+            "2026-W20",
+            [
+                _make_order(
+                    "Alice",
+                    "alice@x.com",
+                    [_make_item("Burger")],
+                    total=Decimal("10.025"),
+                )
+            ],
+        )
+        assert payload["lines"][0]["amount"] == "10.03"
+
 
 class TestCheckcomponentsSend:
     @patch("functions.aggregate_orders.handler.put_summary")