feat: task trash, triage trash and retention settings for every area; admin can forbid keeping things for good

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

internal/api/server.go

@@ -207,6 +207,10 @@ func (s *Server) Router() http.Handler {
 		r.Post("/api/v1/tasks/{id}/unlink", s.handleUnlinkEnhancedTask)
 		r.Post("/api/v1/tasks/reorder", s.handleReorderTasks)
 		r.Post("/api/v1/tasks/clear-done", s.handleClearDoneTasks)
+		r.Get("/api/v1/tasks/trash", s.handleGetTaskTrash)
+		r.Post("/api/v1/tasks/trash/empty", s.handleEmptyTaskTrash)
+		r.Post("/api/v1/tasks/trash/{id}/restore", s.handleRestoreTrashedTask)
+		r.Delete("/api/v1/tasks/trash/{id}", s.handlePurgeTrashedTask)
 		r.Post("/api/v1/task-lists/{id}/tasks/reorder", s.handleReorderTasks)
 
 		// Task Lists & Shares