Materialize instances when a quest definition is created

create_quest_definition persisted the rule, definition, assignees and
windows but never called regenerate_for_definition, unlike edit, assign,
unassign and activate. A new task therefore had no quest_instances rows
and stayed off the panel board until an unrelated write regenerated it.

Call regenerate_for_definition after the DAO write, using the host
clock and the default horizon, and add a test that a created weekly
definition has only today-or-later instances.

Update test fixtures that relied on create writing no instances: close
the seeded one-day rules with end_date, clear the table before the gated
materialize walk, and adjust the admin regenerate tests to the new
create behaviour.

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

tests/test_api_panel.py

@@ -149,13 +149,18 @@ async def _seed_household(
             (today + datetime.timedelta(days=3)).isoformat(),
             today=today,
         )
-        # The stale quest is created AFTER the today walk, so its only
-        # instance is the yesterday one written below.
+        # The stale quest's rule ends YESTERDAY, so create's own
+        # regeneration writes nothing and its only instance is the
+        # yesterday one written below.
         await _quest_definitions.create_quest_definition(
             database,
             "Stale chore",
             _recurrence.ScheduleRule.from_dict(
-                {"rule_type": "daily", "start_date": yesterday_iso}
+                {
+                    "rule_type": "daily",
+                    "start_date": yesterday_iso,
+                    "end_date": yesterday_iso,
+                }
             ),
             [ada.id],
             [("morning", "09:00")],