feat(waitlist): optional event waitlist with FIFO promote.

Commercial calendars opt in via settings.waitlist_enabled; join when full;
auto-promote on cancel/decline/expire with email and in-app notify.

Refs EventHub/EventHubBack#72

src/logic/logic_booking.erl

@@ -8,7 +8,7 @@
   list_bookings_admin/0, get_booking_admin/1,
   list_event_bookings/1, list_event_bookings/2,
   process_timeout_bookings/0, process_reminders/0, cancel_pending_for_owner/1,
-  cancel_pending_for_calendar/1]).
+  cancel_pending_for_calendar/1, can_manage_event_bookings/2]).
 
 %%%-------------------------------------------------------------------
 %%% @doc Создание бронирования с учётом commercial / confirmation / capacity.
@@ -133,7 +133,13 @@ confirm_booking(UserId, BookingId, decline) ->
         true ->
           case ensure_pending_actionable(Booking) of
             {ok, _} ->
-              core_booking:update(BookingId, [{status, cancelled}]);
+              case core_booking:update(BookingId, [{status, cancelled}]) of
+                {ok, _} = Ok ->
+                  _ = logic_waitlist:maybe_promote(Booking#booking.event_id),
+                  Ok;
+                Err ->
+                  Err
+              end;
             {error, Reason} ->
               {error, Reason}
           end;
@@ -155,7 +161,14 @@ cancel_booking(BookingId, UserId) ->
           {ok, Booking};
         _ ->
           case Booking#booking.user_id =:= UserId of
-            true -> core_booking:update(BookingId, [{status, cancelled}]);
+            true ->
+              case core_booking:update(BookingId, [{status, cancelled}]) of
+                {ok, _} = Ok ->
+                  _ = logic_waitlist:maybe_promote(Booking#booking.event_id),
+                  Ok;
+                Err ->
+                  Err
+              end;
             false -> {error, access_denied}
           end
       end;
@@ -462,7 +475,12 @@ maybe_timeout(#booking{id = Id, event_id = EventId, created_at = Created} = Book
                       Now = calendar:universal_time(),
                       _ = core_booking:update(Id, [{status, confirmed}, {confirmed_at, Now}]);
                     false ->
-                      _ = core_booking:update(Id, [{status, cancelled}])
+                      case core_booking:update(Id, [{status, cancelled}]) of
+                        {ok, _} ->
+                          _ = logic_waitlist:maybe_promote(EventId);
+                        _ ->
+                          ok
+                      end
                   end;
                 false ->
                   ok
@@ -553,7 +571,18 @@ ensure_not_past_pending(B) ->
 
 -spec mark_expired(binary()) -> {ok, #booking{}} | {error, term()}.
 mark_expired(BookingId) ->
-  core_booking:update(BookingId, [{status, expired}]).
+  case core_booking:get_by_id(BookingId) of
+    {ok, #booking{event_id = EventId}} ->
+      case core_booking:update(BookingId, [{status, expired}]) of
+        {ok, _} = Ok ->
+          _ = logic_waitlist:maybe_promote(EventId),
+          Ok;
+        Err ->
+          Err
+      end;
+    {error, _} = Err ->
+      Err
+  end.
 
 -spec event_started(#event{}, non_neg_integer()) -> boolean().
 event_started(#event{start_time = Start}, NowSec) ->