Add GET /api/v1/home for the Home dashboard

home.Service aggregates the Home screen from the services that own each
value, at "now" in the household's zone: the date label, tonight's dinner
from the current week's plan (null with no plan), the pending Side quest
count from the deck, the Supply run status of the upcoming week or else
the current one, and recentUpdates.unread.

unread is whether a notification was stored in notification_outbox after
household_settings.updates_seen_at (or at all while it is null), read
through the new notify.StoredSince over the HasNotificationSince query.
Nothing writes updates_seen_at yet; the updates task adds that.

Tests under America/Chicago show tonight's dinner flips at local
midnight, not UTC midnight, and cover no plan, no suggestions, the
Supply run choice and unread.

Maestro task 9ccfc3a6-cc7b-493a-aa4b-2b455d26f4df.

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

internal/notify/notify.go

@@ -189,6 +189,22 @@ func (s *Service) EmitTx(ctx context.Context, tx *sql.Tx, ev Event) error {
 	})
 }
 
+// StoredSince reports whether a notification was stored after since, or
+// at all when since is nil. An event counts once it is stored for any
+// channel, whatever became of its delivery; one whose preference switches
+// every channel off is never stored and never counts.
+func (s *Service) StoredSince(ctx context.Context, since *time.Time) (bool, error) {
+	var after sql.NullString
+	if since != nil {
+		after = sql.NullString{String: timestamp(*since), Valid: true}
+	}
+	found, err := db.New(s.st.Reader).HasNotificationSince(ctx, after)
+	if err != nil {
+		return false, fmt.Errorf("notify: read notifications since %s: %w", after.String, err)
+	}
+	return found, nil
+}
+
 // emitTx stores ev in tx for each channel that channels chooses from the
 // preference of ev's type.
 func (s *Service) emitTx(ctx context.Context, tx *sql.Tx, ev Event, channels func(db.NotificationPref) ([]Channel, error)) error {