Persist skip_on_away on quest definitions

Add a skip_on_away flag to quest_definitions (migration 8, additive
column defaulting to 1 so existing rows keep today's behaviour). The
admin create/edit routes accept it as an optional boolean (create
defaults true, an omitted edit field keeps the stored value) and the
definition payload returns it. Materialisation generates instances on
absent dates when the flag is false.

Task: ded75ab8-0219-4d52-aefa-82c09e0b5e6b

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

custom_components/nestquest/core/materialize.py

@@ -18,7 +18,8 @@ The walk is deterministic and idempotent:
   :class:`~.presence.PresenceEngine` from that same coherent read.
 - For each date in the range, each definition whose decoded rule
   :func:`~.recurrence.occurs_on` on that date, each assignee who is
-  ``is_present`` on that date and each declared window, one instance is
+  ``is_present`` on that date (or every assignee, when the definition's
+  ``skip_on_away`` is off) and each declared window, one instance is
   written through :class:`~.dao_instances.QuestInstancesDao.upsert_if_valid`
   with a ``generated_at`` stamp shared by the whole batch (one coherent
   time per run).
@@ -208,7 +209,8 @@ async def materialize(
 
     definitions = [
         (snapshot.definition.id, _decode_rule(snapshot),
-         snapshot.assignees, snapshot.windows)
+         snapshot.assignees, snapshot.windows,
+         snapshot.definition.skip_on_away)
         for snapshot in snapshots
     ]
 
@@ -229,13 +231,15 @@ async def materialize(
     cursor = start
     while cursor <= end:
         iso = cursor.isoformat()
-        for definition_id, rule, assignees, windows in definitions:
+        for (
+            definition_id, rule, assignees, windows, skip_on_away
+        ) in definitions:
             if not occurs_on(rule, cursor):
                 continue
             for child in assignees:
                 if child_filter is not None and child.id not in child_filter:
                     continue
-                if not engine.is_present(child.id, cursor):
+                if skip_on_away and not engine.is_present(child.id, cursor):
                     continue
                 for window in windows:
                     written = await instances.upsert_if_valid(