2a48fb7af0
- DB migration v32: task_assignments and event_assignments join tables with CASCADE delete; existing assigned_to data migrated automatically - Tasks API: accepts assigned_to as array, returns assigned_users[] with json_group_array; filter uses EXISTS on task_assignments - Calendar API: same pattern via event_assignments; serializeEvent includes assigned_users array - Recurring task completion copies all assignments to the new instance - Frontend: shared UserMultiSelect component with avatar stack display (renderAvatarStack, renderUserMultiSelect, getSelectedUserIds, bindUserMultiSelect); tasks.js and calendar.js use it in modals and card/agenda views - CSS: user-multi-select.css with avatar-stack and user-ms classes - 14 new tests covering CRUD, JSON aggregation, EXISTS filter, and CASCADE behavior for both task and event assignments Closes #125