fix(dashboard): 'Paid This Month' actually uses calendar month

The dashboard card labeled 'Paid This Month' was summing the
last 60 days of PayrollRecords — identical to the payroll
dashboard's 'Paid (60D)' card. Misleading at best, wrong at
worst when explaining the dashboard to a non-developer.

Now filters by date__year + date__month (current calendar month
only). Added 3 regression tests: excludes 45-day-old payment,
includes 1st-of-month payment, returns 0 cleanly when nothing
paid yet this month.

Found during Konrad's 15 May audit of dashboard numbers.

core/tests.py

@@ -3008,3 +3008,60 @@ class WorkHistoryTeamFilterTests(TestCase):
         resp = self.client.get(f'/history/?team={self.team_a.id}')
         self.assertIn(f'team={self.team_a.id}', resp.context['filter_params'])
         self.assertEqual(resp.context['selected_team'], str(self.team_a.id))
+
+
+class DashboardPaidThisMonthTests(TestCase):
+    """Regression: 'Paid This Month' on the admin dashboard must be the
+    CURRENT CALENDAR MONTH only — not a rolling 60-day window. Previously
+    this card showed the same value as the payroll dashboard's 'Paid (60D)'
+    card, which was misleading when explaining the dashboard to a
+    non-developer."""
+
+    @classmethod
+    def setUpTestData(cls):
+        cls.admin = User.objects.create_user(
+            username='admin', password='pw', is_staff=True, is_superuser=True,
+        )
+        cls.worker = Worker.objects.create(
+            name='Pay W', id_number='PW1', monthly_salary=Decimal('6000'),
+        )
+
+    def setUp(self):
+        self.client.force_login(self.admin)
+
+    def test_paid_this_month_excludes_last_month(self):
+        """A payment dated 45 days ago (almost certainly in the prior
+        calendar month) must NOT count toward 'Paid This Month'."""
+        today = datetime.date.today()
+        forty_five_days_ago = today - datetime.timedelta(days=45)
+
+        # In-month payment (counts)
+        PayrollRecord.objects.create(
+            worker=self.worker, amount_paid=Decimal('1000.00'), date=today,
+        )
+        # 45-days-old payment (does NOT count — almost always prior month)
+        PayrollRecord.objects.create(
+            worker=self.worker, amount_paid=Decimal('9999.00'),
+            date=forty_five_days_ago,
+        )
+
+        resp = self.client.get('/')
+        self.assertEqual(resp.context['paid_this_month'], Decimal('1000.00'))
+
+    def test_paid_this_month_includes_first_of_month(self):
+        """A payment dated 1st of the current month counts (boundary case)."""
+        today = datetime.date.today()
+        first_of_month = today.replace(day=1)
+
+        PayrollRecord.objects.create(
+            worker=self.worker, amount_paid=Decimal('500.00'),
+            date=first_of_month,
+        )
+
+        resp = self.client.get('/')
+        self.assertEqual(resp.context['paid_this_month'], Decimal('500.00'))
+
+    def test_paid_this_month_zero_when_no_payments(self):
+        """No payments in the current month → zero (not None)."""
+        resp = self.client.get('/')
+        self.assertEqual(resp.context['paid_this_month'], Decimal('0.00'))

core/views.py

@@ -372,10 +372,16 @@ def index(request):
         pending_adjustments_sub  = _o['pending_adj_sub']
         outstanding_by_project   = _o['outstanding_by_project']
 
-        # Sum total paid out in the last 60 days
-        sixty_days_ago = timezone.now().date() - timezone.timedelta(days=60)
+        # === PAID THIS MONTH (calendar month, 1st → today) ===
+        # The dashboard card is labeled "Paid This Month" and must reflect
+        # the CURRENT CALENDAR MONTH only — not a rolling 60-day window.
+        # The payroll dashboard has its own separate "Paid (60D)" card if
+        # the rolling-window view is wanted. Filtering by date__year +
+        # date__month is unambiguous and matches the label exactly.
+        _today_dt = timezone.now().date()
         paid_this_month = PayrollRecord.objects.filter(
-            date__gte=sixty_days_ago
+            date__year=_today_dt.year,
+            date__month=_today_dt.month,
         ).aggregate(total=Sum('amount_paid'))['total'] or Decimal('0.00')
 
         # Count and total balance of active loans