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_core_sweep.py

@@ -102,15 +102,20 @@ async def _seed_missed_household(
             database, "Old chore", rule, [ada.id], [("evening", "18:30")]
         )
         await materialize(database, yesterday_iso, yesterday_iso, today=yesterday)
-        # A quest due TODAY (created after the yesterday walk so it has
-        # no past-due instance): the post-downtime catch-up run's
+        # A quest due TODAY only (created after the yesterday walk so it
+        # has no past-due instance; ``end_date`` keeps create's horizon
+        # regeneration to today): the post-downtime catch-up run's
         # target — inside [watermark=today, later_today) but not
         # inside the day-one sweep's window.
         await create_quest_definition(
             database,
             "Recoverable chore",
             ScheduleRule.from_dict(
-                {"rule_type": "daily", "start_date": today_iso}
+                {
+                    "rule_type": "daily",
+                    "start_date": today_iso,
+                    "end_date": today_iso,
+                }
             ),
             [ada.id],
             [("afternoon", "17:00")],