Ticket archival system implementation with cascade and auto-archive functionality: **Model Changes (app/models/ticket.rb):** - Added `archived` (boolean) and `archived_at` (timestamp) columns via migration - Added `archive!` method that only works for done/cancelled tickets - Added `unarchive!` method with optional cascade to subtasks - Added `auto_archive_if_cancelled` callback that auto-archives cancelled tickets - Cascade logic: archiving an epic archives all subtasks; archiving all subtasks archives parent epic - Added `active` scope (excludes archived) and `archived` scope (only archived) **MCP Tools (app/controllers/api/v1/mcp_controller.rb):** - `archive_ticket` - archive a single ticket - `archive_tickets` - archive multiple tickets at once - `list_archived_tickets` - list only archived tickets - `unarchive_ticket` - unarchive a ticket (with unarchive_subtasks option) - Updated `handle_list_tickets` to add `include_archived` filter (default: false) **API Changes:** - Updated `/api/v1/tickets` index to support `include_archived` filter - Updated TicketSerializer to expose `archived` and `archived_at` **Query Updates:** - ProjectSerializer: `open_ticket_count` and `ticket_count` exclude archived - DashboardController: `kanban` action excludes archived by default, supports `show_archived` param - McpController: `handle_get_status` excludes archived tickets - DashboardController: `calculate_agent_stats` excludes archived from counts **UI Changes:** - Kanban board: removed `cancelled` status from @all_statuses - Kanban board: added "Show Archived" toggle (show_archived parameter) - Avo admin: added `archived` and `archived_at` fields to Ticket resource - Avo admin: added ArchiveTicket and UnarchiveTicket actions - JavaScript: added `toggleArchived` action to kanban-filter controller **Tests (spec/models/ticket_spec.rb):** - Tests for archive! with done/cancelled/non-done tickets - Tests for cascade logic (epic -> subtasks, all subtasks -> epic) - Tests for unarchive! with and without subtasks option - Test for auto-archive callback - Tests for active and archived scopes **Important Implementation Details:** - Fixed infinite recursion in archive! by marking ticket as archived FIRST, then cascading - Used `update_columns` for parent epic archiving to avoid callbacks and infinite loops - Auto-archive uses `update_column` to avoid triggering additional callbacks