Improve auto-handling of "local" timestamps

for non-Rattail DBs where timestamps are local instead of UTC

tailbone/views/master.py

@@ -424,6 +424,7 @@ class MasterView(View):
             'url': lambda obj: self.get_action_url('view', obj),
             'checkboxes': checkboxes,
             'checked': self.checked,
+            'assume_local_times': self.has_local_times,
         }
         if 'main_actions' not in kwargs and 'more_actions' not in kwargs:
             main, more = self.get_grid_actions()
@@ -2961,6 +2962,16 @@ class MasterView(View):
         Coerce the given data dict record, to a "row" dict suitable for use
         when writing directly to XLSX file.
         """
+        data = dict(data)
+        for key in data:
+            value = data[key]
+
+            # make timestamps local, "zone-naive"
+            if isinstance(value, datetime.datetime):
+                value = localtime(self.rattail_config, value, tzinfo=False)
+
+            data[key] = value
+
         return data
 
     def results_csv(self):
@@ -3504,6 +3515,7 @@ class MasterView(View):
             'model_class': getattr(self, 'model_class', None),
             'action_url': self.request.current_route_url(_query=None),
             'use_buefy': self.get_use_buefy(),
+            'assume_local_times': self.has_local_times,
         }
         if self.creating:
             kwargs.setdefault('cancel_url', self.get_index_url())